Bio 462- The Urinary System - The Urinary System Renal functions o Filter wastes and excrete o Glucogenogenesis during prolonged fasting o Producing

Bio 462- The Urinary System - The Urinary System Renal...

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The Urinary SystemRenal functionsoFilter wastes and excreteoGlucogenogenesis during prolonged fastingoProducing hormones rennin and erythropoietinRenin acts as an enzyme to regulate blood pressure and kidney functionErythropoietin: stimulates red blood cell productionoMetabolizing vitamin D to its active formUrinary system: kidneys, urinary bladder, ureters and urethraKidney AnatomyLocation and External AnatomyBean-shapedRenal hilum: leads to renal sinus where ureter, blood vessels and lymphatics all joinAdrenal gland3 layers of supportive tissu:oRenal fasciaoPerirenal fat capsuleoFibrous capsuleFatty layer helps kep kidney in place preventing hydronephrosis and necrosis/renal failureInternal Anatomy3 distinct regions: cortex, medulla and pelvisRenal cortexRenal medullaMedullary/renal pyramidsoPapilla points internallyRenal columns: separate pyramidsLobes: 8Renal pelvisMajor calyces  minor calyces: collect urine and empty into the renal pelvisPyelitis: infection of renal pelvis and calycesPyelonephritis: infection/inflammation of kidneysBlood and Nerve SupplyRenal artereies: delive ¼ of total cardiac output to kidneys each minuteoDivides into 5 segmental arteries  arcuate arteries  cortial radiate arteriesVeins leave along same path arteries entered; cortical radiate  arcuate  interlobar  renal veinsRenal plexus: nerve supply for kidney and ureter, supplied by sympathetic fibers
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NephronsNephrons: structural and functional units of the kidneys; connect to collecting ducts, form urineGlomerulus: capillariesRenal tubuleGlomerular/Bowman’s capsuleRenal corpuscle: glomerular capsule and glomerulusGlomerular capillaries are fenestrated – allows for solute-rich fluid/filtrate to pass from blood to glomerular capsuleVisceral layer contains podocytes – terminate in foot processesFiltration slits: clefts between foot processes where filtration can enter capsular spaceProximal convoluted tubule (PCT)  Loop of Henle/nephron loop/Henle’s loop  distal convoluted tubule (DCT)  collecting ductCollecting ducts give pyramids striped lookPCT: cuboidal epithelial cells, with dense microvillioIncreases surface area and absorption abilityLoop of Henle: ascending and descendingoDescending: thin segment, permeable to wateroAscending: thick segment, not permeable to waterTransition from DCT to collecting duct:oIntercalated cells: maintain acid-base balance of bloodoPrincipal cells: maintain bodys water and sodium balance2 types of nephronsoCortical nephrons – 85%oJuxtamedullary nephrons: produce concentrated urineNephron Capillary BedsoGlomerulus and peritubular capillariesoGlomerulus:FiltrationAfferent and efferent arteiolesBlood pressure in glomerulus capillary bed high becauseArterioles are high-resistance vessesls
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  • Fall '13
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  • Physiology, Anatomy, glomerular capillaries, glomerular capsule, glomerular blood pressure

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