NURS617 EXAM 6 Questions And Solutions. Already Passed

NURS617 EXAM 6 Questions And Solutions. Already Passed Nephron + parts of nephron - answers -functional unit of the kidney; consists of the following: -glomerulus: cluster of tiny blood vessels; filters blood & selectively reabsorbs material into blood, secretes others to be secreted in urine via hydrostatic pressure -bowman capsule: filtrates; grf -basement membrane: within glomerulus; determines permeability of solutes -tubular components: proximal tubule, loop of henle, distal convoluted tube, collecting tubule (see other note for roles of each) **no ability to regenerate nephrons; older age=decreased nephrons=decreased kidney function 4 parts of the nephron tubule + roles: in order - answers 1. Proximal tubule: drains bowman capsule; reabsorption of electrolytes 2. Loop of henle: where adh exerts effects; urine volume/concentration 3. Distal convoluted tubule: reabsorb na+, cl-, ca+2, mg+2 4. Collecting tubule: joins tubules to collect filtrate for urine; where aldosterone exerts na+ reabsorption & k+ secretion; where thiazide diuretics inhibit na+ reabsorption Juxtaglomerular complex: role - answers -increase in bp=vessels relax in kidneys -decrease in bp=vessels constrict in kidneys 3 feedback mechanisms to keep blood flow + gfr consistent - answers 1. Autoregulation/myogenic response: intrinsic ability of arteries to constrict when blood pressure rises and to vasodilate when it decreases. 2. Humoral: vasoconstriction (angiotensin ii/adh/endothelines) or vasodilation (dopamine, no, prostaglandins) 3. Tubuloglomerular feedback (tgf): controls rate of renin release (enzyme needed to convert angiotensinogen to angiotensin ii; also increases na+ reabsorption via adrenal stimulation to release aldosterone) **kidneys receive 20-25% of cardiac output 3 factors: how kidneys produce concentrated or dilute urine - answers 1. Osmolarity: exchange of solutes between descending and ascending loops loops of henle + capillaries in medullary kidney 2. Adh + its actions: adh present=water reabsorbed, adh absent=water excreted into urine 3. Water permeability: increase in permeability=decrease in urine flow + concentration *kidneys also regulate ph via conserving or eliminating h+ Renal clearance - answers -volume of plasma cleared each minute of any substance that finds its way into urine -urine concentration x urine flow (ml/min) -determined by ability of substance to be filtered, secreted, or reabsorbed -glucose=not normally detected in urine; reabsorbed in tubules Addison's disease + kidneys - answers -adrenal glands do not produce enough of the hormones cortisol or aldosterone -causes increase in k+, decrease in na+ d/t increase in diuresis; leads to hypotension, shock Atrial natriuretic peptide (anp): role on kidney function - answers -promotes vasodilation/acts as diuretic; secreted by cells of atria (heart) -helps conserve na+ by inhibiting aldosterone -increases gfr & renal blood flow Renin-angiotensin-aldosterone system - answers -decreased blood pressure causes the juxtaglomerular cells of kidneys to secrete renin - converts angiotensinogen (inactive) to angiotensin i (active) which is then converted into angiotensin ii by angiotensin-converting enzyme (ace) -angiotensin ii stimulates the adrenal cortex to secrete aldosterone -leads to absorption of na and increased blood pressure -once blood pressure is restored, there is a decreased drive to stimulate renin release High uric acid: causes + ci - answers -gout, kidney stones; product of protein metabolism -rate of reabsorption exceeds secretion -ci: aspirin, thiazide + loop diuretics (d/t low extracellular fluid & increased uric acid reabsorption) Loop diuretics: examples + action + ae - answers -furosemide, bumetanide, torsemide -non potassium sparing -acts on ascending loop of henle -ae: hypokalemia, ototoxicity (lasix) Osmotic diuretics: examples + action + ae - answers -mannitol -acts on proximal tubule -ae: hypotension, hypovolemia Thiazide diuretics: examples + action + ae - answers -hctz, chlorothiazide -early distal tubule -ae: hyperuricemia, hypokalemia Potassium sparing diuretics: examples + action + ae - answers -aldactone, amiloride, eplerenone -aldosterone agonists; decrease na+ reabsorption, decrease k+ secretion -ae: hyperkalemia Gfr: stages of kidney disease - answers 1-- normal : 90 2-- mildly decreased: 60 - 89 3-- moderately decreased: 30-59 4-- severely decreased: 15-29 5-- kidney failure (requires dialysis): 15 Renal function tests - answers -24h urine specimen: throw out first specimen, start 24h collection after -gfr: regulated by constriction/relaxation of arterioles; best measure of kidney function!! -creatinine: 0.6-1.2; increase=decreased kidney function; used to estimate gfr since it is not reabsorbed or secreted in tubules -bun: 10-20; increased=decreased kidney function; influenced by protein intake (nitrogen byproduct), hydration status, creatinine is not!! -specific gravity: increases w/ dehydration, decreased w/ inability to concentrate urine Acute kidney injury (aki) - answers -rapid loss of renal function due to damage to the kidneys; formerly called acute renal failure -causes increase in nitrogenous wastes, impairs fluid/electrolyte balance -can be reversed if corrected before permanent damage occurs -can be d/t decreased blood flow (pre-renal), dx that disrupt kidney structures (intrarenal), or interfere w/ urine elimination (post-renal) -risk factors: htn, older age, long term immunosuppressive rx, nsaids, obesity, diabetes Azotemia - answers -accumulation of nitrogenous wastes in blood (uric acid, creatinine, urea) -causes decrease in gfr -uremia can cause neuropathy, restless leg syndrome -increased risk for thrombosis d/t impaired platelet function -s/s: n/v, lethargy, confusion, coma...leads to uremic encephalopathy & death if no tx d/t increased ammonia levels Pre-renal failure - answers -causes: dehydration, decreased perfusion d/t sepsis, vasoactive drugs, hemorrhage, hf/shock -s/s: sharp decline in urine output, elevated bun to serum creatinine ratio (15:1 or 20:1; normal=10:1) *most common form of aki Intra-renal failure - answers -d/t ischemia associated w/ pre-renal failure -causes: obstruction, intrarenal constrictions (vasoactive drugs), acute glomerulonephritis, acute pyelonephritis