Ch. 25

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urinary system components
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Terms in this set (56)
renal corpusclelarge bulbous region of nephron with renal cortexrenal corpuscle composed of whatglomerulus and Bowmans capsule(glomerular capsule)glomerulusfenestrated capillary prevent filtration of blood cells & large proteinglomerulus blood enters throughafferent arterioleglomerulus blood exits throughefferent arterioleBowmans capsulesurrounds glomerulus and collects filtrateinternal visceral layer of Bowmanscovers glomerulus capillaries, visceral cells(podocytes)external parietal layer ofBowmans capsuleCapsular space of Bowman's capsulespace between the two layers(receive filtrate)2 types of nephronscortical and juxtamedullarycortical nephronsshort loops of Henle are contained almost entirely within cortex-.juxtamedullary nephronslong loops of Henle extend deep into medullajuxtaglomerular apparatus locatedwhere afferent and efferent arterioles enter and leave glomerulusJGA function:helps regulate filtration of blood and monitors blood pressurewhat 2 cells make up JGAmacula dense and jga cellsmacula densacells of DCT & they regulate renin releasejuxtaglomerular cellssmooth muscle that contract or relax to regulate afferent diameter/release renin3 processes of urine formationfiltration, reabsorption, secretionurine filtrationoccurs at renal corpuscle, water enter capsular space & separated fluid is filtrateurine reabsorptionmove out of filtrate back into blood vessels, solutes are reabsorbedurine secretionmove out of blood into filtrate, materials go to tubules to be excretednet filtration pressurethe difference between net hydrostatic pressure and net osmotic pressureglomerular hydrostatic pressure- blood pressure in the glomerular capillaries - tends to push water and solutes out of plasma and into the filtrateblood colloid osmotic pressure-pressure exerted by blood due to plasma proteins -pulls fluid back into glomerulusNet filtration pressure equationNFP=GBHP-BCOPGlomerular Filtration Rate (GFR)the amount of filtrate formed per minute by the two kidneys combinedsympathetic nervous system GFRvasoconstriction of afferent arteriole, GFR would be decreased; vasodilate of afferent arteriole, GFR would increaseAngiotensin II GFRvasoconstrictor, reduces GFR and renal blood flow, stimulates production of aldosteronealdosterone GFRpromotes sodium reabsorptionantidiuretic hormone GFRpromotes reabsorption of water, decreases urine volume and maintains blood volumeatrial natriuretic hormone GFRstimulates kidney to excrete sodium and increases urine volumeReabsorption and Secretion in PCTsubstances returned to circulation & pct moves substances/sodium, glucose & amino acids pumped out of pctreabsorption and secretion in DCT80% recovered water/sodium and chloride are reabsorbed/hydrogen ions & bicarbonate reabsorb or secrete to maintain blood phreabsorption and secretion in loop of henleurea is main substance secreted at nephron loopcollecting ductsprincipal and intercalated cells/urine volume regulated by ADH from pituitary glandbicarbonate, hydrogen ions, and PHIf blood is too acidic, that means there is an increase in H+ in the blood and a decrease of HCO3- • To return blood to normal pHo HCO3- is reabsorbed from tubular fluid into blood o H+ secreted from the blood into tubular fluido Results in increased blood pH and decrease urine pH • If blood is too alkaline, theno HCO3- is secreted into the tubular fluid from the blood o H+ are reabsorbed from tubular fluid into bloodo Results in decreased blood pH and increase urine pHvitamin d synthesisYou need Vitamin D to absorb calcium/calcitriol/neurotransmitter releaseerythropoiesiskidney produce EPO due to low blood oxygen & leads to loss of EPO production/anemiaNormal characteristics of urineColor - pale yellow (straw) to amber Clarity - clear or transparent, but will become cloudy when standing Odor - aromatic Specific gravity - measures concentration: 1.005 - 1.030 pH - 4.5 - 8ureteres carry urine fromkidney to bladder by peristalsis/transitional epitheliumurinary bladdercollects and stores urine from ureters/500-600 mL/detrusor muscle/trigonedetrusor musclemuscularis of bladdertrigonesmooth triangular region/funnels urine into urethrainternal urethral sphincterinvoluntary smooth muscle/superior sphincter/restrict release of urineexternal urethral sphinctervoluntary skeletal muscle/restrict release of urinemictruitionurination, the voluntary releasing of urine from the bladder/requires conscious, voluntary relaxation of external urethral sphincter