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red blood cell : small (7–8 μm) biconcave cell without mitochondria (and in mammals without nuclei) that is packed with hemoglobin, giving the cell its red color; transports oxygen through the body
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semilunar valve : membranous flap of connective tissue between the aorta and a ventricle of the heart (the aortic or pulmonary semilunar valves)
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serum : plasma without the coagulation factors
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sinoatrial (SA) node : the heart’s internal pacemaker; located near the wall of the right atrium
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stroke volume> : - the volume of blood pumped into the aorta per contraction of the left ventricle
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superior vena cava : drains blood from the jugular vein that comes from the brain and from the veins that come from the arms
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systemic circulation : flow of blood away from the heart to the brain, liver, kidneys, stomach, and other organs, the limbs, and the muscles of the body, and then the return of this blood to the heart
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systole : contraction phase of cardiac cycle when the ventricles are pumping blood into the arteries
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tricuspid valve : one-way membranous flap of connective tissue between the atrium and the ventricle in the right side of the heart; also known as atrioventricular valve
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unidirectional circulation : flow of blood in a single circuit; occurs in fish where the blood flows through the gills, then past the organs and the rest of the body, before returning to the heart
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vasoconstriction : narrowing of a blood vessel
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vasodilation : widening of a blood vessel
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vein : blood vessel that brings blood back to the heart
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vena cava : major vein of the body returning blood from the upper and lower parts of the body; see the superior vena cava and inferior vena cava
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ventricle : (heart) large inferior chamber of the heart that pumps blood into arteries
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venule : blood vessel that connects a capillary bed to a vein
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white blood cell : large (30 μm) cell with nuclei of which there are many types with different roles including the protection of the body from viruses and bacteria, and cleaning up dead cells and other waste
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Solute concentrations across a semi-permeable membranes influence the movement of water and solutes across the membrane. It is the number of solute molecules and not the molecular size that is important in osmosis. Osmoregulation and osmotic balance are important bodily functions, resulting in water and salt balance. N...
https://openstax.org/books/biology/pages/41-chapter-summary
The kidneys are the main osmoregulatory organs in mammalian systems; they function to filter blood and maintain the osmolarity of body fluids at 300 mOsm. They are surrounded by three layers and are made up internally of three distinct regions—the cortex, medulla, and pelvis.
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The blood vessels that transport blood into and out of the kidneys arise from and merge with the aorta and inferior vena cava, respectively. The renal arteries branch out from the aorta and enter the kidney where they further divide into segmental, interlobar, arcuate, and cortical radiate arteries.
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The nephron is the functional unit of the kidney, which actively filters blood and generates urine. The nephron is made up of the renal corpuscle and renal tubule. Cortical nephrons are found in the renal cortex, while juxtamedullary nephrons are found in the renal cortex close to the renal medulla. The nephron filters...
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There are three steps in the formation of urine: glomerular filtration, which occurs in the glomerulus; tubular reabsorption, which occurs in the renal tubules; and tubular secretion, which also occurs in the renal tubules.
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Many systems have evolved for excreting wastes that are simpler than the kidney and urinary systems of vertebrate animals. The simplest system is that of contractile vacuoles present in microorganisms. Flame cells and nephridia in worms perform excretory functions and maintain osmotic balance. Some insects have evolved...
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Ammonia is the waste produced by metabolism of nitrogen-containing compounds like proteins and nucleic acids. While aquatic animals can easily excrete ammonia into their watery surroundings, terrestrial animals have evolved special mechanisms to eliminate the toxic ammonia from their systems. Urea is the major byproduc...
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Hormonal cues help the kidneys synchronize the osmotic needs of the body. Hormones like epinephrine, norepinephrine, renin-angiotensin, aldosterone, anti-diuretic hormone, and atrial natriuretic peptide help regulate the needs of the body as well as the communication between the different organ systems.
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afferent arteriole : arteriole that branches from the cortical radiate artery and enters the glomerulus
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ammonia : compound made of one nitrogen atom and three hydrogen atoms
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ammonotelic : describes an animal that excretes ammonia as the primary waste material
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angiotensin converting enzyme (ACE) : enzyme that converts angiotensin I to angiotensin II
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angiotensin I : product in the renin-angiotensin-aldosterone pathway
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angiotensin II : molecule that affects different organs to increase blood pressure
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anti-diuretic hormone (ADH) : hormone that prevents the loss of water
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antioxidant : agent that prevents cell destruction by reactive oxygen species
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arcuate artery : artery that branches from the interlobar artery and arches over the base of the renal pyramids
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ascending limb : part of the loop of Henle that ascends from the renal medulla to the renal cortex
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blood urea nitrogen (BUN) : estimate of urea in the blood and an indicator of kidney function
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Bowman's capsule : structure that encloses the glomerulus
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calyx : structure that connects the renal pelvis to the renal medulla
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cortex (animal) : outer layer of an organ like the kidney or adrenal gland
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cortical nephron : nephron that lies in the renal cortex
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cortical radiate artery : artery that radiates from the arcuate arteries into the renal cortex
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countercurrent exchanger : peritubular capillary network that allows exchange of solutes and water from the renal tubules
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countercurrent multiplier : osmotic gradient in the renal medulla that is responsible for concentration of urine
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descending limb : part of the loop of Henle that descends from the renal cortex into the renal medulla
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distal convoluted tubule (DCT) : part of the renal tubule that is the most distant from the glomerulus
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efferent arteriole : arteriole that exits from the glomerulus
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electrolyte : solute that breaks down into ions when dissolved in water
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flame cell : (also, protonephridia) excretory cell found in flatworms
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glomerular filtration : filtration of blood in the glomerular capillary network into the glomerulus
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glomerular filtration rate (GFR) : amount of filtrate formed by the glomerulus per minute
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glomerulus (renal) : part of the renal corpuscle that contains the capillary network
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hilum : region in the renal pelvis where blood vessels, nerves, and ureters bunch before entering or exiting the kidney
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inferior vena cava : one of the main veins in the human body
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interlobar artery : artery that branches from the segmental artery and travels in between the renal lobes
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juxtaglomerular cell : cell in the afferent and efferent arterioles that responds to stimuli from the macula densa
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juxtamedullary nephron : nephron that lies in the cortex but close to the renal medulla
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kidney : organ that performs excretory and osmoregulatory functions
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lobes of the kidney : renal pyramid along with the adjoining cortical region
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loop of Henle : part of the renal tubule that loops into the renal medulla
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macula densa : group of cells that senses changes in sodium ion concentration; present in parts of the renal tubule and collecting ducts
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Malpighian tubule : excretory tubules found in arthropods
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medulla : middle layer of an organ like the kidney or adrenal gland
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microvilli : cellular processes that increase the surface area of cells
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molality : number of moles of solute per kilogram of solvent
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molarity : number of moles of solute per liter of solution
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mole : gram equivalent of the molecular weight of a substance
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nephridia : excretory structures found in annelids
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nephridiopore : pore found at the end of nephridia
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nephron : functional unit of the kidney
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non-electrolyte : solute that does not break down into ions when dissolved in water
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osmoconformer : organism that changes its tonicity based on its environment
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osmoregulation : mechanism by which water and solute concentrations are maintained at desired levels
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osmoregulator : organism that maintains its tonicity irrespective of its environment
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osmotic balance : balance of the amount of water and salt input and output to and from a biological system without disturbing the desired osmotic pressure and solute concentration in every compartment
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osmotic pressure : pressure exerted on a membrane to equalize solute concentration on either side
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perirenal fat capsule : fat layer that suspends the kidneys
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peritubular capillary network : capillary network that surrounds the renal tubule after the efferent artery exits the glomerulus
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proximal convoluted tubule (PCT) : part of the renal tubule that lies close to the glomerulus
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renal artery : branch of the artery that enters the kidney
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renal capsule : layer that encapsulates the kidneys
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renal column : area of the kidney through which the interlobar arteries travel in the process of supplying blood to the renal lobes
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renal corpuscle : glomerulus and the Bowman's capsule together
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renal fascia : connective tissue that supports the kidneys
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renal pelvis : region in the kidney where the calyces join the ureters
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renal pyramid : conical structure in the renal medulla
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renal tubule : tubule of the nephron that arises from the glomerulus
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renal vein : branch of a vein that exits the kidney and joins the inferior vena cava
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renin-angiotensin-aldosterone : biochemical pathway that activates angiotensin II, which increases blood pressure
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segmental artery : artery that branches from the renal artery
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semi-permeable membrane : membrane that allows only certain solutes to pass through
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transport maximum : maximum amount of solute that can be transported out of the renal tubules during reabsorption
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tubular reabsorption : reclamation of water and solutes that got filtered out in the glomerulus
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tubular secretion : process of secretion of wastes that do not get reabsorbed
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urea cycle : pathway by which ammonia is converted to urea
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ureotelic : describes animals that secrete urea as the primary nitrogenous waste material
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ureter : urine-bearing tube coming out of the kidney; carries urine to the bladder
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uric acid : byproduct of ammonia metabolism in birds, insects, and reptiles
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urinary bladder : structure that the ureters empty the urine into; stores urine
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urine : filtrate produced by kidneys that gets excreted out of the body
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vasa recta : peritubular network that surrounds the loop of Henle of the juxtamedullary nephrons
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