Renal Physiology Flashcards
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
