Renal Physiology Flashcards
(24 cards)
kidney insufficiency due to reduced blood flow?
prerenal
kidney insufficiency due to glomerulonephritis, tubular necrosis, and vasculitis?
intrarenal
kidney insufficiency due to obstruction of urinary tract?
postrenal
- will cause decreased GFR, high serum creatinine, azotemia, uremia
- low tubular function, less K secretion
- electrolyte imbalance, oliguria, sodium retention
- leads to peripheral, pulmonary edema and HTN
volume overload
major force causing filtration in glomerular capillary?
hydrostatic pressure
filtration opposed by _____ in glomerular capillary
colloid osmotic pressure of blood
the ______ charge in the glomerular filtrating membrane restricts protein filtration, if reduced can have proteinuria
negative
- absorbs 60-70% of GFR including salt and water
- absorbs 100% glucose and amino acids
- secretes uric acid, drugs
- high reabsorption rate
proximal tubule
- impermeable to water
- reabsorbs 25% of salt from filtrate
- reabsorbs Mg
- Na/K2Cl cotransporter
acending loop of Henle
- moderate permeability to water and ions
- no transporters, shows diffusion of NaCl, water, and urea
- passively reabsorbes water via medullary hypertonicity, concentrating segment, makes urine hypertonic
descending loop of Henle
- reabsorption on NaCl, secretion of K
- depends on aldosterone, ADH
distal tubule
- reabsorption of NaCl, secretion of K
- depends on aldosterone and ADH
- ENac, principal and intercalated cells
collecting tubules
clearance of ______ is used to measure GFR
creatinine
normal value of FEna?
1-3%
BUN/CR:
- ______ is freely filtered so it provides info on glomerular function
- ______ is filtered and reabsorbed in tubules, so it gives estimate of tubular function
creatinine
BUN
normal average value for BUN/CR?
15
BUN/Cr ratio greater than 15 in _________ b/c glomerular function is impaired but tubular function is maintained, urine osmolarity normal, decreased GFR and azotemia
prerenal failure
BUN/Cr ratio is less than 15 in _______ failure b/c glomerular function maintained but tubular function is impaired, Fena >3% b/c inability to concentrate urine
intrarenal (tubular necrosis)
BUN/Cr less than 15 in __________, glomerular pressures and function impaired and tubular function impaired at later stages
postrenal
- osmoreceptors in anterior hypothalamus
- produces and supraoptic and periventricular nuclei
- promote water reabsorption
- through V2 receptors, insert aquaporins
antiduretic hormone (vasopressin)
- ex furosemide, bumetanide, ethacrynic acid
- thick ascending limb of Henle
- Na/K/2Cl tansporter
loop diuretics
work at distal tubule, NaCl cotransporter inhibitor
thiazides (chlorothiazide, benthothiaxide, metolazone)
- work at prinicpal cells of collecting tubule
- antagonist of aldosterone or Na channel blockers
K sparing (spironolactone, amiloride, triamterine)
- work at proximal tbule
- carbonic anhydrase inhibition, bicarb reabsorption reducer
acetazolamide, methazolamide
