Renal Physiology

Question 1

kidney insufficiency due to reduced blood flow?

Answer 1

prerenal

Question 2

kidney insufficiency due to glomerulonephritis, tubular necrosis, and vasculitis?

Answer 2

intrarenal

Question 3

kidney insufficiency due to obstruction of urinary tract?

Answer 3

postrenal

Question 4

• 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

Answer 4

volume overload

Question 5

major force causing filtration in glomerular capillary?

Answer 5

hydrostatic pressure

Question 6

filtration opposed by _____ in glomerular capillary

Answer 6

colloid osmotic pressure of blood

Question 7

the ______ charge in the glomerular filtrating membrane restricts protein filtration, if reduced can have proteinuria

Answer 7

negative

Question 8

• absorbs 60-70% of GFR including salt and water
• absorbs 100% glucose and amino acids
• secretes uric acid, drugs
• high reabsorption rate

Answer 8

proximal tubule

Question 9

• impermeable to water
• reabsorbs 25% of salt from filtrate
• reabsorbs Mg
• Na/K2Cl cotransporter

Answer 9

acending loop of Henle

Question 10

• 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

Answer 10

descending loop of Henle

Question 11

• reabsorption on NaCl, secretion of K

- depends on aldosterone, ADH

Answer 11

distal tubule

Question 12

• reabsorption of NaCl, secretion of K
• depends on aldosterone and ADH
• ENac, principal and intercalated cells

Answer 12

collecting tubules

Question 13

clearance of ______ is used to measure GFR

Answer 13

creatinine

Question 14

normal value of FEna?

Answer 14

1-3%

Question 15

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

Answer 15

creatinine

BUN

Question 16

normal average value for BUN/CR?

Answer 16

15

Question 17

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

Answer 17

prerenal failure

Question 18

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

Answer 18

intrarenal (tubular necrosis)

Question 19

BUN/Cr less than 15 in __________, glomerular pressures and function impaired and tubular function impaired at later stages

Answer 19

postrenal

Question 20

• osmoreceptors in anterior hypothalamus
• produces and supraoptic and periventricular nuclei
• promote water reabsorption
• through V2 receptors, insert aquaporins

Answer 20

antiduretic hormone (vasopressin)

Question 21

• ex furosemide, bumetanide, ethacrynic acid
• thick ascending limb of Henle
• Na/K/2Cl tansporter

Answer 21

loop diuretics

Question 22

work at distal tubule, NaCl cotransporter inhibitor

Answer 22

thiazides (chlorothiazide, benthothiaxide, metolazone)

Question 23

• work at prinicpal cells of collecting tubule

- antagonist of aldosterone or Na channel blockers

Answer 23

K sparing (spironolactone, amiloride, triamterine)

Question 24

• work at proximal tbule

- carbonic anhydrase inhibition, bicarb reabsorption reducer

Answer 24

acetazolamide, methazolamide