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are several different types of angular movements, including flexion, extension, hyperextension, abduction, adduction, and circumduction. Flexion, or bending, occurs when the angle between the bones decreases. Moving the forearm upward at the elbow or moving the wrist to move the hand toward the forearm are examples of... |
shrugged and the scapulae return to their normal position from an elevated position. Dorsiflexion is a bending at the ankle such that the toes are lifted toward the knee. Plantar flexion is a bending at the ankle when the heel is lifted, such as when standing on the toes. Supination is the movement of the radius and u... |
is an example of a hinge joint. (credit: modification of work by Brian C. Goss) Pivot Joints Pivot joints consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis. An example of a pivot joint is the joi... |
ts extension b. allows only gliding movement c. allows abduction or adduction d. allows rotation Rheumatologist Rheumatologists are medical doctors who specialize in the diagnosis and treatment of disorders of the joints, muscles, and bones. They diagnose and treat diseases such as arthritis, musculoskeletal disorders,... |
.6 Chapter 29 | The Musculoskeletal System 1287 29.4 | Muscle Contraction and Locomotion In this section, you will explore the following questions: • What are the different types of muscle tissue? • What is the role of muscle contraction in locomotion? Connection for AP® Courses Muscles move bones, and, in turn, muscle... |
or more of the seven science practices. Big Idea 4 Enduring Understanding 4.A Biological systems interact, and these systems and their interactions possess complex properties. Interactions within biological systems lead to complex properties. Essential Knowledge 4.A.4 Organisms exhibit complex properties due to intera... |
in and myosin). Actin is a globular contractile protein that interacts with myosin for muscle contraction. Skeletal muscle also has multiple nuclei present in a single cell. Smooth muscle tissue occurs in the walls of hollow organs such as the intestines, stomach, and urinary bladder, and around passages such as the re... |
a dense line running vertically through the middle called a Z disc or Z line. The Z discs mark the border of units called sarcomeres, which are the functional units of skeletal muscle. One sarcomere is the space between two consecutive Z discs and contains one entire A band and two halves of an I band, one on either s... |
has binding sites for myosin attachment. Strands of tropomyosin block the binding sites and prevent actin–myosin interactions when the muscles are at rest. Troponin consists of three globular subunits. One subunit binds to tropomyosin, one subunit 1290 Chapter 29 | The Musculoskeletal System binds to actin, and one su... |
zone of overlap, in which thin filaments and thick filaments occupy the same area, increases as the thin filaments move inward. ATP and Muscle Contraction The motion of muscle shortening occurs as myosin heads bind to actin and pull the actin inwards. This action requires energy, which is provided by ATP. Myosin binds... |
myosin, which allows the cross-bridge cycle to start again and further muscle contraction can occur (Figure 29.37). Watch this video (http://openstaxcollege.org/l/contract_muscle) explaining how a muscle contraction is signaled. Why can’t actin and myosin interact in the absence of calcium? a. Actin binding sites are ... |
in head bends with the release of ADP and inorganic phosphate. Another ATP binds to the myosin head, causing the cross-bridge to detach and returning myosin to the cocked configuration. b. The actin head forms a cross-bridge with myosin which initiates the power stroke. During the power stroke, the actin head bends wit... |
pling Excitation–contraction coupling is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction. The trigger for calcium release from the sarcoplasmic reticulum into the sarcoplasm is a neural signal. Each skeletal muscle fiber is controlled by a motor neu... |
potential is considerably smaller (0.07 V); therefore, the small value is expressed as millivolts (mV) or 70 mV. Because the inside of a cell is negative compared with the outside, a minus sign signifies the excess of negative charges inside the cell, −70 mV. If an event changes the permeability of the membrane to Na+... |
breaking down ACh so that it does not remain bound to ACh receptors, which would cause unwanted extended muscle contraction (Figure 29.38). 1296 Chapter 29 | The Musculoskeletal System Figure 29.38 This diagram shows excitation-contraction coupling in a skeletal muscle contraction. The sarcoplasmic reticulum is a spec... |
filaments overlap, allowing myosin to bind to actin. If more cross-bridges are formed, more myosin will pull on actin, and more tension will be produced. The ideal length of a sarcomere during production of maximal tension occurs when thick and thin filaments overlap to the greatest degree. If a sarcomere at rest is s... |
oskeletal System KEY TERMS abduction when a bone moves away from the midline of the body acetylcholinesterase (AChE) enzyme that breaks down ACh into acetyl and choline actin globular contractile protein that interacts with myosin for muscle contraction adduction movement of the limbs inward after abduction amphiarthro... |
lies between adjacent vertebrae from the second cervical vertebra to intramembranous ossification process of bone development from fibrous membranes inversion soles of the feet moving inward, toward the midline of the body irregular bone bone with complex shapes; examples include vertebrae and hip bones joint point at... |
asts release minerals stored in bones retraction movement in which a joint moves back into position after protraction rib one of 12 pairs of long, curved bones that attach to the thoracic vertebrae and curve toward the front of the body to form the ribcage rotational movement movement of a bone as it rotates around its... |
two polymers of actin wound together along with tropomyosin and troponin thoracic cage cartilages (also, ribcage) skeleton of the chest, which consists of the ribs, thoracic vertebrae, sternum, and costal tibia (also, shinbone) large bone of the leg that is located directly below the knee trabeculae lamellae that are ... |
bones in the arm, the forearm, and the hand. The pelvic girdle attaches the lower limbs to the axial skeleton. The lower limb includes the bones of the thigh, the leg, and the foot. 29.2 Bone Bone, or osseous tissue, is connective tissue that includes specialized cells, mineral salts, and collagen fibers. The human sk... |
of a bone as it rotates around its own longitudinal axis. Special movements include inversion, eversion, protraction, retraction, elevation, depression, dorsiflexion, plantar flexion, supination, pronation, and opposition. Synovial joints are also classified into six different categories on the basis of the shape and ... |
the following would most be at risk if someone had a defective thoracic cage? a. middle ear b. brain c. spinal cord d. heart 5. Which type of skeletal system of animals is composed of a hard skeletal layer found on the exterior of the organism? a. hydrostatic skeleton b. exoskeleton c. axial skeleton d. appendicular s... |
oid 15. _____ is a characteristic of the synovial fluid. a. Stability b. Lubrication c. Minor movement d. Increase of friction 16. Which of the following is an example of a pivot joint? a. elbow b. thumb c. hip d. the joint of the wrist 17. Synovial joints allow different types of movement. Turning your head to look ov... |
26. You discover the carcass of an unusual new organism on the beach while on vacation. As a scientist, you decide This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 29 | The Musculoskeletal System 1305 to chemically analyze the carcass in order to characterize it. The chemical ana... |
. Abnormally weak bones prone to breakage and fracturing upon mild trauma would be expected. In severe cases, individuals may have abnormal bone formation as manifested by thicker and longer bones resulting in a taller stature. c. Bones are abnormally weak and highly flexible. In severe cases, individuals may have abno... |
Both the hip joint and knees are extended. c. The hip joint is extended and the knees are flexed. d. The hip joint is flexed and the knees are extended. 33. What is the main structural difference between synovial joints and cartilaginous and fibrous joints? a. Synovial joints allow movement while fibrous and cartilagi... |
rigor mortis. d. Myosin heads will not detach from the actin- binding sites, resulting in muscle stiffness. In a live person this causes “writer’s cramp”, while in a recently dead person it results in rigor mortis. 36. What is the difference between voluntary and involuntary muscles? Give an example of each. This Open... |
biopolymers. Note that this is a logarithm scale not a linear scale. So that the difference in toughness of keratin and bone is roughly 100 and the difference in rigidity of these to materials is nearly that large. A. Use this graph to pose questions about the fitness of various biological solutions to the problem of ... |
the right lung to accommodate space for the heart. A dog’s nose (right) has a slit on the side of each nostril. When tracking a scent, the slits open, blocking the front of the nostrils. This allows the dog to exhale though the now-open area on the side of the nostrils without losing the scent that is being followed. ... |
. Energy production in cellular respiration requires O2, and CO2 is produced as a toxic by-product. Some animals, such as worms and amphibians, use their entire body surface for respiration. Terrestrial animals, including humans, needed a more efficient system for gas exchange. So, take a deep breath (pun intended!) as... |
, different organisms have devised different means of obtaining oxygen from the surrounding atmosphere. The environment in which the animal lives greatly determines how an animal respires. The complexity of the respiratory system is correlated with the size of the organism. As animal size increases, diffusion distances... |
works by diffusion across the outer membrane. (credit: Stephen Childs) Skin and Gills Earthworms and amphibians use their skin (integument) as a respiratory organ. A dense network of capillaries lies just below the skin and facilitates gas exchange between the external environment and the circulatory system. The respi... |
V, between each gill, then travels out of the top of the V. Veins travel into the gill from the base of the gill arch, and arteries travel back out on the opposite side. A close-up image of a single gill shows that water travels over the gill, passing over deoxygenated veins first, then over oxygenated arteries. Figur... |
to the trachea and lungs. Thus, inhalation serves several purposes in addition to bringing oxygen into the respiratory system. 1314 Chapter 30 | The Respiratory System Figure 30.7 Air enters the respiratory system through the nasal cavity and pharynx, and then passes through the trachea and into the bronchi, which bri... |
of cartilage. (credit: modification of work by Gray's Anatomy) Lungs: Bronchi and Alveoli The end of the trachea bifurcates (divides) to the right and left lungs. The lungs are not identical. The right lung is larger and contains three lobes, whereas the smaller left lung contains two lobes (Figure 30.9). The muscular... |
alveolar sacs, each containing 20 to 30 alveoli that are 200 to 300 microns in diameter. Gas exchange occurs only in alveoli. Alveoli are made of thin-walled parenchymal cells, typically one-cell thick, that look like tiny bubbles within the sacs. Alveoli are in direct contact with capillaries (one-cell thick) of the ... |
arynx connects the nasal cavity to the lungs, while the larynx connects the oral cavity to the lungs. c. The oral and nasal cavities connect to separate lungs. d. The nasal and oral cavities combine above the pharynx. Protective Mechanisms The air that organisms breathe contains particulate matter such as dust, dirt, v... |
important application of the principles of diffusion that we explored in the chapter on passive transport. In addition, gas exchange provides the oxygen needed for aerobic cellular respiration and for the removal of carbon dioxide produced as a metabolic waste product. Gas movement into or out of the lungs is dependen... |
System 1319 The structure of the lung maximizes its surface area to increase gas diffusion. Because of the enormous number of alveoli (approximately 300 million in each human lung), the surface area of the lung is very large (75 m2). Having such a large surface area increases the amount of gas that can diffuse into an... |
amount of air left in the lungs after forceful respiration. Lung Volumes and Capacities (Avg Adult Male) Volume/ Capacity Definition Volume (liters) Equations Tidal volume (TV) Amount of air inhaled during a normal breath Expiratory reserve volume (ERV) Amount of air that can be exhaled after a normal exhalation 0.5 1... |
There is always some air left in the lungs after a maximal exhalation. If this residual volume did not exist and the lungs emptied completely, the lung tissues would stick together and the energy necessary to re-inflate the lung could be too great to overcome. Therefore, there is always some air remaining in the lungs... |
get the air out of his or her lungs, and it takes a long time to reach the maximal exhalation volume. In either case, breathing is difficult and complications arise. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 30 | The Respiratory System 1321 Respiratory Therapist Respirator... |
(760 mm Hg) (0.0004) = 0.3 mm Hg. At high altitudes, Patm decreases but concentration does not change; the partial pressure decrease is due to the reduction in Patm. When the air mixture reaches the lung, it has been humidified. The pressure of the water vapor in the lung does not change the pressure of the air, but i... |
and a PCO2 alveolar P O2 alveolar P O2 RQ in the alveoli of 40 mm Hg, the alveolar PO2 = inspired PO2 − ( ) is equal to: alveolar P O2 = 150 mm Hg − ( 40 mm Hg 0.8 ) = mm Hg. = 100 mm Hg) (Figure 30.13). = 100 mm Hg) than blood PO2 = (45 mm Hg). CO2 diffuses down its pressure gradient, moving out of the capillaries an... |
drives CO2 out of tissue cells and into the capillaries. = 100 mm Hg, whereas the venous PCO2 = 100 mm Hg, but in the tissue cells, PO2 = 40 mm Hg and a PCO2 is lower PALVO 2 = 45 mm Hg. = 40 This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 30 | The Respiratory System 1323 Figure... |
intercostal muscles, and bound by the chest wall. The bottom of the lungs is contained by the diaphragm, a skeletal muscle that facilitates breathing. Breathing requires the coordination of the lungs, the chest wall, and most importantly, the diaphragm. Types of Breathing Amphibians have evolved multiple ways of breat... |
Decades of research by paleontologists have shown that birds evolved from therapods, meat-eating dinosaurs (Figure 30.14). In fact, fossil evidence shows that meat-eating dinosaurs that lived more than 100 million years ago had a similar flow-through respiratory system with lungs and air sacs. Archaeopteryx and Xiaoti... |
air and lung volume decreases. In the next few sections, the process of human breathing will be explained. The Mechanics of Human Breathing Boyle’s Law is the gas law that states that in a closed space, pressure and volume are inversely related. As volume decreases, pressure increases and vice versa (Figure 30.15). Th... |
ic cavity. This increases the pressure within the thoracic cavity relative to the environment, and air rushes out of the lungs. The movement of air out of the lungs is a passive event. No muscles are contracting to expel the air. Each lung is surrounded by an invaginated sac. The layer of tissue that covers the lung an... |
of breaths per minute is the respiratory rate. On average, under non-exertion conditions, the human respiratory rate is 12–15 breaths/minute. The respiratory rate contributes to the alveolar ventilation, or how much air moves into and out of the alveoli. Alveolar ventilation prevents carbon dioxide buildup in the alve... |
Babies born prematurely sometimes do not produce enough surfactant. As a result, they suffer from respiratory distress syndrome, because it requires more effort to inflate their lungs. Surfactant is also important for preventing collapse of small alveoli relative to large alveoli. Lung Resistance and Compliance Pulmon... |
lack of airway recruitment. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 30 | The Respiratory System 1331 Figure 30.18 The ratio of FEV1 (the amount of air that can be forcibly exhaled in one second after taking a deep breath) to FVC (the total amount of air that can be forci... |
As a result, the intrapleural pressure is more negative at the base of the lung than at the top, and more air fills the bottom of the lung than the top. Likewise, it takes less energy to pump blood to the bottom of the lung than to the top when in a prone position. Perfusion of the lung is not uniform while standing o... |
protein called hemoglobin. Hemoglobin is a quaternary protein comprise of four iron-containing heme groups; iron has a great affinity for oxygen. (We know this because iron rusts when exposed to air.) Information presented and the examples highlighted in the section support concepts outlined in Big Idea 4 of the AP® B... |
As a result, oxygenated arterial blood where the Hb is carrying four oxygen molecules is bright red, while venous blood that is deoxygenated is darker red. Figure 30.19 The protein inside (a) red blood cells that carries oxygen to cells and carbon dioxide to the lungs is (b) hemoglobin. Hemoglobin is made up of four s... |
increase in carbon dioxide and subsequent decrease in pH reduce the affinity of hemoglobin for oxygen. The oxygen dissociates from the Hb molecule, shifting the oxygen dissociation curve to the right. Therefore, more oxygen is needed to reach the same hemoglobin saturation level as when the pH was higher. A similar sh... |
the majority of carbon dioxide molecules (85 percent) are carried as part of the bicarbonate buffer system. In this system, carbon dioxide diffuses into the red blood cells. Carbonic anhydrase (CA) within the red blood cells quickly converts the carbon dioxide into carbonic acid (H2CO3). Carbonic acid is an unstable i... |
oglobin preferentially over oxygen. As a result, oxygen cannot bind to hemoglobin, so very little oxygen is transported through the body (Figure 30.22). Carbon monoxide is a colorless, odorless gas and is therefore difficult to detect. It is produced by gas-powered vehicles and tools. Carbon monoxide can cause headache... |
terminal region of the lung where gas exchange occurs anatomical dead space anatomical block (also, anatomical shunt) region of the lung that lacks proper ventilation/perfusion due to an bicarbonate (HCO3 − ) ion ion created when carbonic acid dissociates into H+ and (HCO3 − ) bicarbonate buffer system system in the b... |
can be inspired after a normal inhalation This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 30 | The Respiratory System 1339 intercostal muscle muscle connected to the rib cage that contracts upon inspiration intrapleural space space between the layers of pleura larynx voice box, ... |
ratio of carbon dioxide production to each oxygen molecule consumed respiratory rate number of breaths per minute restrictive disease disease that results from a restriction and decreased compliance of the alveoli; respiratory distress syndrome and pulmonary fibrosis are examples sickle cell anemia genetic disorder th... |
the system. In the lungs, particles are trapped in a mucus layer and transported via cilia up to the esophageal opening at the top of the trachea to be swallowed. 30.2 Gas Exchange across Respiratory Surfaces The lungs can hold a large volume of air, but they are not usually filled to maximal capacity. Lung volume mea... |
30.4 Transport of Gases in Human Bodily Fluids Hemoglobin is a protein found in red blood cells that is comprised of two alpha and two beta subunits that surround an iron-containing heme group. Oxygen readily binds this heme group. The ability of oxygen to bind increases as more oxygen molecules are bound to heme. Dis... |
c. nasal cavity, trachea, larynx, bronchi, bronchioles, alveoli d. nasal cavity, trachea, larynx, bronchi, bronchioles, alveoli 3. What advantages does warming air within the nasal passages provide? 6. The total lung capacity is calculated using which formula? a. b. residual volume + tidal volume + inspiratory reserve... |
move up, causing expiration. b. They move up, causing inspiration, and move down, causing expiration. c. They relax, causing inspiration, and contract, causing expiration. d. They contract, causing inspiration, and relax, causing expiration. 10. How would paralysis of the diaphragm alter inspiration? a. b. c. d. It wo... |
. If ventilation is high, the respiratory rate will increase while the volume of air per breath decreases. If ventilation is low, the respiratory rate will increase while the volume of air per breath is decreased. If ventilation is high, the respiratory rate will increase while the volume of air per breath increases. I... |
arynx warms the air. d. The closed-off compartments of the larynx trap impurities in the air and warm the air. 22. If you were travelling in a miniaturized ship through the respiratory system, from the pharynx to an alveolus, which structures would you pass along the way, and in what order? a. binding to hemoglobin b. ... |
blood than in the body tissues d. lower in the blood than in the air and lower in the blood than in the body tissues 25. What conditions of the lungs would cause a an increase in FEV1/FVC? What about a decrease FEV1/ FVC? a. This ratio increases as the lungs become stiff and less pliable, increasing further when there... |
floor to a greater extent than the top of the lung. What implication could this have on ventilation in the lungs? a. Concentration gradient leads to increased ventilation further down in the lung. b. Pleural pressure gradient leads to increased ventilation further down in the lung. c. Pleural pressure gradient leads t... |
cells are sickle-shaped, increasing oxygen perfusion into the blood. It is a deficiency disease in which red blood cells are sickle-shaped, reducing oxygen perfusion into the blood. It is a deficiency disease in which red blood cells are sickle-shaped, increasing oxygen perfusion into the blood. TEST PREP FOR AP® COUR... |
area and reach the lungs. Typically, air is supplied artificially using a squeezable bag that connects to the top of the tube.The illustration shows the human respiratory system. The nasal cavity is a wide cavity above and behind the nostrils, and the pharynx is the passageway behind the mouth. The nasal cavity and ph... |
0 to 100 percent as the partial pressure of oxygen increases from 0 to 100. What happens as the curve levels off around a partial pressure of 60 mmHg? a. As the percent saturation of hemoglobin increases to its maximum, hemoglobin’s affinity for oxygen increases as the availability of oxygen increases. b. As the perce... |
for hemoglobin. Based on the graph, what would likely cause the curve to shift to the right, as shown by the dotted plot line? a. decreasing carbon dioxide, increasing pH, or decreasing temperature b. decreasing carbon dioxide, decreasing pH, or decreasing temperature c. d. increasing carbon dioxide, increasing pH or ... |
be correlated with increased lactic acid concentrations in the blood. Another mutation, PPARA, was found to be correlated with fatty acid production, which is typically seen during hibernation (Ge et al., Molecular Genetics and Metabolism, 106, 2012; Lorenzo et al., Nature Genetics, 46, 2014) C. Analyze these observat... |
of dollars are spent each year researching ways to prevent and treat it. For example, researchers have been trying to find a way to get damaged cardiac muscle to repair itself. A team of researchers at the Weizmann Institute of Science recently discovered that activating a protein called ERBB2 causes heart cells in ad... |
Framework provide a transparent foundation for the AP® Biology course, an inquiry-based laboratory experience, instructional activities, and AP® exam questions. A learning objective merges required content with one or more of the seven science practices. Big Idea 1 The process of evolution drives the diversity and uni... |
brates, this is a closed-loop system, in which the blood is not free in a cavity. In a closed circulatory system, blood is contained inside blood vessels and circulates unidirectionally from the heart around the systemic circulatory route, then returns to the heart again, as illustrated in Figure 31.2a. As opposed to a... |
well as dissolved gases, as shown in Figure 31.3a. Organisms that are more complex but still only have two layers of cells in their body plan, such as jellies (Cnidaria) and comb jellies (Ctenophora) also use diffusion through their epidermis and internally through the gastrovascular compartment. Both their internal a... |
ambered heart with two atria and a single ventricle. (c) Reptiles also have two circulatory routes; however, blood is only oxygenated through the lungs. The heart is three chambered, but the ventricles are partially separated so some mixing of oxygenated and deoxygenated blood occurs except in crocodilians and birds. (... |
oxygen-rich blood through the systemic circulatory system and deoxygenated blood to the pulmocutaneous circuit. For this reason, amphibians are often described as having double circulation. Most reptiles also have a three-chambered heart similar to the amphibian heart that directs blood to the pulmonary and systemic c... |
in a water-based liquid called plasma. Red blood cells are specialized to carry hemoglobin (Hgb), a quaternary protein that transports oxygen and some carbon dioxide around the body, to and from the heart and lungs. Hemoglobin also has an affinity for carbon monoxide, a toxic and deadly gas. Variants of hemoglobin hel... |
uring Understanding 4.A 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models. 2.19 The student is able to make predictions about how positive feedback mechanisms amplify activities and processes in organisms based on scientific theories and models. Biological s... |
stabilizing pH, temperature, osmotic pressure, and by eliminating excess heat. Blood supports growth by distributing nutrients and hormones, and by removing waste. Blood plays a protective role by transporting clotting factors and platelets to prevent blood loss and transporting the disease-fighting agents or white bl... |
. Invertebrates that utilize hemolymph rather than blood use different pigments to bind to the oxygen. These pigments use copper or iron to bind the oxygen. Invertebrates have a variety of other respiratory pigments. Hemocyanin, a blue-green, copper-containing protein, illustrated in Figure 31.6b is found in mollusks, ... |
the blood vessels and capillaries and may help with gas exchange and the passage of red blood cells through narrow vessels. Nitroglycerin, a heart medication for angina and heart attacks, is converted to NO to help relax the blood vessels and increase oxygen flow through the body. A characteristic of red blood cells i... |
granules in their cytoplasm. Some leukocytes become macrophages that either stay at the same site or move through the blood stream and gather at sites of infection or inflammation where they are attracted by chemical signals from foreign particles and damaged cells. Lymphocytes are the primary cells of the immune syst... |
Chapter 31 | The Circulatory System 1359 Figure 31.8 (a) Platelets are formed from large cells called megakaryocytes. The megakaryocyte breaks up into thousands of fragments that become platelets. (b) Platelets are required for clotting of the blood. The platelets collect at a wound site in conjunction with other clot... |
in Figure 31.9, and Rh systems. The surface antigens in the ABO blood group are glycolipids, called antigen A and antigen B. People with blood type A have antigen A, those with blood type B have antigen B, those with blood type AB have both antigens, and people with blood type O have neither antigen. Antibodies called... |
078/1.6 Chapter 31 | The Circulatory System 1361 Which of the following phylogenies, created based on features of the circulatory system of vertebrates, is most accurate? a. A b. B c. C d. D 1362 Chapter 31 | The Circulatory System Play a blood typing game on the Nobel Prize website (http://openstaxcollege.org/l/blood_... |
the pathway of blood through the heart in a previous course, and as a student of biology, you should have some knowledge of this pathway. (No, you do not need to memorize the names of all arteries and veins or the names of the specific valves of the heart.) The heart is a perfect example of the relationship between st... |
biocomplexity due to interactions of the constituent parts. Competition and cooperation are important aspects of biological systems. Essential Knowledge 4.B.2 Specialization of the heart and blood vessels contributes to the overall function of the body. Science Practice Learning Objective 1.4 The student can use repre... |
. c. Red blood cells contain nuclei and hemoglobin, which distributes oxygen throughout the body. White blood cells are primarily involved in the immune response to identify and target pathogens. They lack both nuclei and hemoglobin. d. Red blood cells lack nuclei at maturity and contain hemoglobin, which is involved i... |
flowing backwards into the right ventricle. The left atrium then receives the oxygen-rich blood from the lungs via the pulmonary veins. This blood passes through the bicuspid valve or mitral valve (the atrioventricular valve on the left side of the heart) to the left ventricle where the blood is pumped out through aor... |
allows enough room for vigorous pumping but also keeps the heart in place to reduce friction between the heart and other structures. The heart has its own blood vessels that supply the heart muscle with blood. The coronary arteries branch from the aorta and surround the outer surface of the heart like a crown. They di... |
During (c) atrial systole, the atria contract, pushing blood into the ventricles. The pumping of the heart is a function of the cardiac muscle cells, or cardiomyocytes, that make up the heart muscle. Cardiomyocytes, shown in Figure 31.13, are distinctive muscle cells that are striated like skeletal muscle but pump 136... |
an electrical impulse that causes the characteristic reading of an ECG. The signal is initiated at the sinoatrial valve. The signal then (a) spreads to the atria, causing them to contract. The signal is (b) delayed at the atrioventricular node before it is passed on to the (c) heart apex. The delay allows the atria to... |
limbs. The major arteries diverge into minor arteries, and then smaller vessels called arterioles, to reach more deeply into the muscles and organs of the body. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 31 | The Circulatory System 1371 Figure 31.16 The major human arteries... |
and vasodilation. The arteries have thicker smooth muscle and connective tissue than the veins to accommodate the higher pressure and speed of freshly pumped blood. The veins are thinner walled as the pressure and rate of flow are much lower. In addition, veins are structurally different than arteries in that veins ha... |
factors can affect blood pressure, such as hormones, stress, exercise, eating, sitting, and standing. Blood flow through the body is regulated by the size of blood vessels, by the action of smooth muscle, by one-way valves, and by the fluid pressure of the blood itself. How Blood Flows Through the Body Blood is pushed... |
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