V-Renal Tubular Secretion

Question 1

renal tubular secretion

Answer 1

movement from peritubular capillary/blood back into the tubular lumen/nephron
-to remove all organic compounds entering kidney from plasma

Question 2

where organic cations and anios are secreted?

Answer 2

100% of cations/anions secreted to proximal tubule for excretion
-from peritubular cap to

Question 3

low pH = what back leak

Answer 3

more back leak and less excretion
-membrane is permeable to non ionic forms

Question 4

high pH = what back leak

Answer 4

less back leak and more excretion
-membrane is less permeable to non ionic forms (since less protons in plasma)

Question 5

where K+ is secreted

Answer 5

from peritubular capillary back into nephron @ distal tubule and collecting duct only
-allows for plasma to be quickly controlled

Question 6

5 main regulation factors K+

Answer 6

1. plasma potassium concentration
2. flow of tubular fluid
3. acid base balance
4. aldosterone
5. diuretics

Question 7

plasma potassium concentration

Answer 7

high K+ intake = inc secretion
low K+ intake = dec secretion

Question 8

flow of tubular fluid on K secretion

Answer 8

rise in flow = inc K+ secretin
fall in flow = dec K + secretion

Question 9

acid base balance of K+

Answer 9

alkaline plasma pH = inc K+ secretion
acidic plasma pH = dec secretion

via reg NaKATPase activity and K+ efflux across apical membrane

Question 10

aldosterone

Answer 10

hyperkalemia > inc aldosterone secretion > more K + secreted

by reg NaKATPase activity and efflux across apical membrane

Question 11

diuretics

Answer 11

inhibit Na reabsorption (to cap) upstream of collecting duct > water reabsorption inhibited

so the fluid reaching the collecting duct is inc rate > inc K + secretion and excretion = depletion