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Definition
| secreted by kidneys; acts on erythrocyte progenitors in bone marrow and regulates RBC formation in response to decreased O2 conc.; produced by endothelial cells of peritubular capillaries in renal cortex; used to treat severe anemia |
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Definition
| produced by juxtaglomerular cells in kidney; acid protease involved in control of blood pressure and blood volume; cleaves circulating angiotensin to release ANGIOTENSIN I |
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| connective tissue covering kidney surface; two distinct layers: outer layer of fibroblasts/collagen fibers & inner layer of myofibroblasts |
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Definition
| section cut through kidney cortex at angle perpendicular to surface reveals series of vertical striations that emanate from medulla; each ray contains straight tubules of nephrons and collecting ducts; one ray with collecting duct for group of nephrons that drain into that duct constitutes RENAL SECRETORY UNIT |
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Definition
| regions bet. medullary rays; contain renal corpuscles, convoluted tubules of nephrons, and colecting tubules |
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Definition
| each nephron and its collecting tubule which connects to a collecting duct in the medullary ray |
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Definition
| capillary network in medulla that runs in parallel with the tubules; represent vascular part of countercurrent exchange system that regulates the concentration of urine; efferent arterioles from corpuscles descend into medullary pyramid - ARTERIOLAE RECTAE, make hairpin deep in medullary pyramid, ascend as VENULAE RECTAE |
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Term
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Definition
| tubules in the medulla collectively form these conical structures; caused by tubules' arrangement and differences in length; usually 8-12 in human kidney; bases face cortex, apices toward renal sinus; divided into outer/inner medulla; outer medulla subdivided into outer/inner stripes |
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Term
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Definition
| caps of cortical tissue that lie over pyramids, extend peripherally around lateral portion of pyramid; components of cortical tissue, yet considered medullary; |
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Definition
| reflect number of medullary pyramids (1 pyramid=1 lobe); subdivided into lobules consisting of a central medullary ray and surrounding cortical material; |
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Definition
| fundamental structural and functional unit of the kidney; about 2 million per kidney; production of urine; collecting ducts responsible for final concentration of urine; |
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Definition
| beginning of the nephron; consists of glomerulus |
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Definition
| tuft of capillaries composed of 10-20 capillary loops, surrounded by Bowman's capsule; glomerular capillaries produce GLOMERULAR ULTRAFILTRATE; supplied by an AFFERENT ARTERIOLE and drained by EFFERENT ARTERIOLE |
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Term
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Definition
| double-layered epithelial cup surrounding glomerulus; initial portion of nephron |
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Definition
| in cortical labyrinth; connects to collecting tubule, often through a connecting tubule, forms uriniferous tubule; 1/3 length of PCT; reabsorption of Na+, bicarbonate; secretion of K+, H+ (acidification of urine), ammonium |
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Term
| order of nephron tubular segments |
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Definition
| proximal convoluted tubule, proximal straight tubule, thin descending limb (including hairpin turn of loop of Henle), thin ascending limb, distal straight tubule, distal convoluted tubule |
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Definition
| apex of medullary pyramid; papillary ducts open into MINOR CALYX on AREA CRIBROSA of papilla. |
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Term
| endothelium of glomerular capillaries |
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Definition
| numerous fenestrations; large number of aquaporin water channels that allow fast movement of water through epithelium |
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Term
| glomerular basement membrane (GBM) |
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Definition
| thick basal lamina; product of endothelium/podocytes of visceral layer of Bowman's capsule; PAS prominent; mostly type IV collagen, proteoglycans, mutiladhesive glycoproteins; LAMINA RARA EXTERNA, LAMINA RARA INTERNA, LAMINA DENSA |
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Term
| visceral layer of Bowman's capsule |
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Definition
| podocytes, visceral epithelial cells; podocytes extend processes around capillaries - PEDICELS; pedicels interdigitate with one another, spaces between - FILTRATION SLITS |
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Term
| filtration slit diaphragm |
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Definition
| ultrathin zipper-like sheet that spans the filtration slits of pedicel interdigitation; NEPHRIN - transmembrane protein, key structural/functional component of slit diaphragm; nephrin molec's from opposite pedicels interact in center of slit |
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Term
| glomerular filtration barrier |
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Definition
| endothelium of glomerular capillaries, visceral layer of Bowman's capsule, glomerular basement membrane, endothelial surface layer (glomerular capillaries), subpodocyte space; active structure that can remodel and modify permeability - not passive |
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Term
| parietal layer of Bowman's capsule |
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Definition
| parietal epithelial cells forming simple squamous epithelium; |
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Definition
| space between visceral and parietal layers of Bowman's capsule; receptacle for the glomerular ultrafiltrate produced by the filtration apparatus of the renal corpuscle; continuous with proximal convoluted tubule |
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Definition
| mesangial cells + their ECM; enclosed by GBM; phagocytosis/endocytosis - removed residues, immune complexes from FSD; structural podocyte support (ECM); secretion of molec's in response to glomerular injury; modulation of glomerular distension in response to blood pressure |
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Definition
| mesangial cells located outside the corpuscle along vascular pole; part of juxtaglomerular apparatus |
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Term
| juxtaglomerular apparatus |
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Definition
| includes macula densa, juxtaglomerular cells, and extraglomerular mesangial cells; regulates blood pressure by activating renin-angiotensin-aldosterone system |
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Definition
| cells of wall of terminal distal straight tubule; narower, taller than other distabl tubule cells; appear crowded; monitor Na+ concentration in tubular fluid, regulating glomerular filtration rate and renin release; decrease in Na = renin secretion |
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Term
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Definition
| modified smooth muscle cells of afferent (sometimes efferent) arteriole; contain secretory granules containing renin; circular nuclei |
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Term
| renin-angiotensin-aldosterone system (RAAS) |
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Definition
| maintains Na+ homeostasis and renal hemodynamics; renin released into bloodstream by juxtaglomerular cells, cleaves angiotensinogen to angiotensin I, converted by ACE to angiotensin II, stim's release of aldosterone from zona glomerulosa of adrenal gland and induces vasoconstriction controlling renal and systemic vascular resistnace, increases reabsorption of Na (& H2O) in collecting ducts = increases blood volume/pressure; increase in blood volume and stretching of juxtaglomerular cells may stop renin secretion |
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Term
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Definition
| water, Na, bicarbonate partially reabsorbed ; glucose completely reabsorbed; creatine, organic acids/bases added by secretory activity of tubule cells |
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Term
| proximal convoluted tubule |
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Definition
| receives ultrafiltrate from Bowman's capsule; cuboidal cells with elaborate specializations: brush border, junctional complex, plicae/folds on lateral surfaces, interdigitation of basal processes of adjacent cells; basal striations |
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Definition
| 120 L/day out of 180 L/day reabsorbed - approx. 65% ultrafiltrate |
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Term
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Definition
| active reabsorption of Na+ (and H2O), passive diffusion of Cl- to maintain neutrality; increase in NaCl in intercellular spaces creates osmotic gradient for H2O, lateral folds separate for distension; cotransport amino acids, glucose for reabsorption |
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Term
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Definition
| H2O transmembrane channel protein; does not require high energy of Na+/K+-ATPase pumps |
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Term
| loop of Henle thin segment |
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Definition
type I epithelium: descending/ascending limbs of short-looped nephrons, no interdigitations, few organelles
type II epithelium: thin descending of long-looped nephrons, taller, abundant organelles, microvilli
type III epithelium: thin descending in inner medulla, thinner epithelium
type IV epithelium: bend of long-looped nephrons & thin ascending, low, flattened, no microvilli |
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Term
loop of Henle:
thin descending limb |
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Definition
| highly permeable to water, much less permeable to solutes (NaCl, urea); PASSIVE movement of H2O into peritubular CT, no ion transport |
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Term
loop of Henle:
thin ascending limb |
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Definition
| highly impermeable to water; no active ion transport; highly permeable to NaCl - passive diffusion into interstitium; Cl- diffuses into interstitium across gradient via Cl- channels, Na+ K+ follow; cells produce UROMODULIN |
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Term
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Definition
| produced by thin ascending loop epithelial cells; influences NaCl reabsorption and urinary concentration ability |
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Term
| distal straight tubule (thick ascending limb) |
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Definition
| electroneutral synporters transport Cl-, Na+, K+ into cell; large cuboidal cells with indistinct lateral margins; nuclei at apical portion, bulges into lumen; extensive basolateral plications with many mitochondria |
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Term
| light cells/collecting duct cells |
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Definition
| principle cells of collecting tubules/ducts; single cilium; small, spherical mitochondria; abundance of ADH; aquaporin-2 channels |
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Term
| dark cells/intercalated cells |
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Definition
| small numbers in collecting tubules/ducts; many mitochondria; microplicae on apical surface (mistakable for microvilli); secrete H+ or bicarbonate depending on needed pH; |
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Term
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Definition
cortex: cells that resemble fibroblasts, occasional macrophages
medulla: cells that resemble myofibroblasts |
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Term
| countercurrent multiplier system |
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Definition
| allows excretion of hyperosmotic urine; LOOP OF HENLE (multiplier; osmotic gradients established along axis of loop), VASA RECTA (exchangers of water/solutes; loops parallel to loop of Henle, maintains osmotic gradient of medulla), COLLECTING DUCT (osmotic equilibrating device; depneds on ADH-dependent AQP-2 |
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Term
| countercurrent multiplier effect |
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Definition
| NaCl conc. in interstitium gradually increases down length of LOH and through thickness of medulla from corticomedullary junction to papilla |
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Term
| countercurrent exchange system |
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Definition
| both arterial and venous sides of vasa recta loop are thin-walled vessels forming plexuses of fenestrated capillaries in medulla. descend - blood loses H2O to interstitium, gains salt; ascend - loses salt, gains H2O |
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Term
| peritubular capillary network |
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Definition
| efferent arterioles of renal corpuscles in cortex branch to form capillary network surrounding tubular portions of nephron in cortex |
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Term
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Definition
| when present, distal convoluted tubules, collecting tubules, and collecting ducts are highly permeable to water |
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Term
| organization of kidney blood supply |
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Definition
| renal artery into each kidney; banches in renal sinus to INTERLOBAR ARTERIES; travel bet. pyramids, turn and follow arched course at pyramid base bet. medulla/cortex - ARCUATE ARTERIES; branch into INTERLOBULAR ARTERIES, ascend toward capsule; branch into AFFERENT ARTERIOLES; after glomerulus, EFFERENT; then peritubular capillaries |
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