animal physiology chapter 14 vocab.
Terms
undefined, object
copy deck
- Osmoregulators
- Animals that maintain an internal osmolarity different from the medium in which that are immersed have been termed osmoregulators.
- Osmoconformer
- An animal that does not actively control the osmotic condition of its body fluids and instead conforms to the osmolarity of the surrounding medium is termed an osmoconformer.
- Osmolytes
- Osmolar homeostasis is achieved by increasing the concentration of intracellular organic osmolyes, substances that, by their presence in high concentrations, act to increase intracellular osmolarity.
- Trimethylamine oxide (TMAO)
- A nitrogenous waste product, probably form choline decomposition.
- Urea
- (NH2)2CO, the primary nitrogenous waste product in the urine of mammals.
- Obligatory osmotic exchanges
- Obligatory osmotic exchanges occur mainly in response to physical factors over which the animal has little or no physiological control.
- Regulated osmotic exchanges
- Regulated osmotic exchanges are physiologically controlled and serve to aid in maintaining internal homeostasis.
- Arginine vasotocin (AVT)
- The permeability of amphibian skin is controlled by a hormone called arginine vasotocin (AVT) or, more simply, vasotocin; like the mammalian antidiuretic hormone (ADH; also called vasopressin), vasotocin enhances water permeability.
- Metabolic water
- Although water is an end product of cellular metabolism, it is produced in small enough quantities that its elimination is not problematic. In fact, this so-called metabolic water is the major source of water for many desert dwellers.
- Countercurrent multiplication
- (note: involves the loop of Henle) the kidneys of binds and mammals utilize countercurrent multiplication to produce hyperosmotic urine, which is more concentrated than the blood plasma.
- Loop of Henle
- The U-shaped portion of the renal tubule that lies in the renal medulla.
- Temporal countercurrent system
- The respiratory loss of water via exhaled air is minimized through a mechanism first discovered in the nose of the desert-dwelling kangaroo rat. This mechanism, termed a temporal countercurrent system, retains most of the respiratory water vapor by condensing it on cooled nasal passages during exhalation.
- Euryhaline
- Euryhaline aquatic animals can tolerate a wide range of salinities.
- Stenohaline
- Stenohaline animals can tolerate only a narrow osmotic range of salinities.
- Chloride cells
- Epithelial cells of fish gills that engage in active transport of salts.
- Salt glands
- Osmoregularory organs that form a hypertonic aqueous exudates by means of active salt secretion into small tubules situated above the eyes, which is excreted via the nostrils; found in many birds and reptiles that live in desert or marine environments.
- Apical
- The apical surface (sometimes referred to as the mucosal or luminal surface) of an epithelial cell faces a space that is continuous with the external world (such as the sea, the pond, the lumen of the gut, or the lumen of a kidney tubule.)
- Basal
- The basal surface (sometimes referred to as the serosal surface) generally bears deep basal clefts and faces an internal compartment containing extracellular fluid.
- F-ATP synthases
- One type of ion-motive ATPase, or pump, found in mitochondria and chloroplasts, which use a proton electrochemical gradient to make ATP.
- V-ATPases
- V-ATPases, or vacuolar-type ATPases, hydrolyze ATP to generate electrochemical gradients, as do P-ATPases.
- P-ATPases
- V-ATPases, or vacuolar-type ATPases, hydrolyze ATP to generate electrochemical gradients, as do P-ATPases.
- Cortex
- The outer layer of the kidney is termed the cortex.
- Medulla
- The inner layer of the kidney, the medulla, sends papillae projecting in to the renal pelvis.
- Renal pelvis
- Cavity at base of each kidney; receives urine from collecting duct system and empties it into ureter.
- Micturition
- Urination
- Urethra
- A channel that passes urine from the bladder out of the body.
- Nephron
- The morphologic and functional unit of the vertebrate kidney; composed of the glomerulus and BowmanÂ’s capsule, the proximal and distal tubules, the loop of Henle (in birds and mammals), and a collecting duct.
- Collecting ducts
- The portion of the mammalian renal tubule in which the final concentration of urine occurs.
- BowmanÂ’s capsule
- (glomerular capsule) A globular expansion at the beginning of a renal tubule that surrounds the glomerulus.
- Glomerulus
- A coiled mass of capillaries.
- Proximal tubule
- The coiled portion of the renal tubule located in the renal cortex, beginning at the glomerulus and leading to (and continuous with) the descending limb of the loop of Henle.
- Distal tubule
- The potion of a renal tubule located in the renal cortex, leading from (and continuous with) the ascending limb of the loop of Henle to the collecting duct.
- Juxtamedullary nephrons
- Juxtamedullary nephrons, which have their glomeruli in the inner part of the cortex and long loops of Henle that plunge deeply into the medulla.
- Cortical nephrons
- Cortical nephrons, which have their glomeruli in the outer cortex and relatively short loops of Henle that extend only a short distance into the medulla.
- Afferent arterioles
- Supplies blood to the nephrons
- Efferent arterioles
- Unlike most other capillary beds, which would join to form veins, the capillaries of the glomerulus come together to form an efferent arteriole.
- Vasa recta
- The capillary network that surrounds the loop of Henle in the tubules of the mammalian kidney.
- Filtration slits and pedicels
- The hydraulic properties of the glomerular apparatus depend primarily on the sievelike filtration slits, which are formed from a rather remarkable assemblage of fine cellular processes termed pedicels.
- Podocytes
- Epithelial cells lining BowmanÂ’s capsule whose foot processes form filtration slits.
- Juxtaglomerular apparatus
- A group of specialized cells situated between the distal renal tubule and the afferent glomerular arterioles that modulate renal blood flow.
- Macula densa
- One of the two specialized cells of the juxtaglomerular apparatus is modified distal-tubule cells, which form the macula densa and monitor the osmolarity and flow of fluid in the distal tubule.
- Juxtaglomerular cells
- One of the two specialized cells of the juxtaglomerular is modified smooth-muscle cells called granular or juxtaglomerular cells, which are located primarily in the wall of the afferent arteriole.
- renin
- A proteolytic enzyme produced by specialized cells in renal arterioles, which converts angiotensinogen to angiotensin.
- Renal clearance
- That volume of plasma containing the quantity of a freely filtered substance that appears in the glomerular filtrate per unit time. Total renal clearance ins the amount of ultrafiltrate produced by the kidney per unit time.
- Brush border
- A free epithelial cell surface bearing numerous microvilli.
- Aldosterone
- A mineralocorticoid secreted by the adrenal cortex; the most important electrolyte controlling steroid, which acts in the renal tubules to increase the reabsorption of sodium.
- 3 mechanisms that account for the aldosterone-induced increase in sodium
- Sodium pump hypothesis, Metabolic hypothesis, Permease hypothesis
- Sodium pump hypothesis
- Activity of the Na+/K+ pump in the basolateral membrane increases, perhaps due to changes in membrane structure that enhance ATPase activity as well as increased synthesis of the pump protein.
- Metabolic hypothesis
- The production of ATP increases, providing more APT to power the Na+/K+ pump, perhaps due to an aldosterone-stimulated increase in fatty acid metabolism.
- Permease hypothesis
- The permeability of the apical membrane to Na+ ions increases, presumably due to an increase in the number of sodium channels in the membrane.
- Atrial natriuretic peptide (ANP)
- (ANP) One of a family of peptide hormones cleaved from a single precursor peptide and produced in the cardiac atria; its physiological effects in clued increased urine output, increased sodium excretion, and receptor-mediated vasodilation, the net result of which is lowered blood pressure.
- Malpighian tubules
- Insect excretory organs responsible for the active secretion of waste products and the formation of urine.
- Ammonotelic
- Pertaining to the excretion of nitrogen in the form of ammonia.
- Ureotelic
- Excreting nitrogen in the form of urea.
- Ornithine-urea cycle
- A cycle succession of reactions that eliminate ammonia and produce urea in the liver of ureotelic organisms.
- Uricolytic pathway
- The pathway through which uric acid or urates are broken down.
- Uricotelic
- Excreting nitrogen in the form of uric acid.