Where dem channels at??

Question 1

Na/K ATPase

Answer 1

baso-lateral membrane

Question 2

NKCC

Answer 2

apical membrane of the TAL

Question 3

H/K ATPase

Answer 3

basolateral membrane

• in acidosis, the pump in the alpha cells goes to remove H+
• in alkalosis, the pump in the beta cells goes to remove K+
• acted on by aldosterone

Question 4

UTA1 and 3

Answer 4

inner medullary collecting duct (inserted by ADH into the later DCT and CD)

Question 5

ADH inserts aquaporins where…?

Answer 5

the apical membrane of the principal cells

*In the absence of ADH, reabsorption of water is normal in the PCT, TAL, and early DCT, but it is absent in the CD

Question 6

ENaC

Answer 6

Apical membrane

*controlled by aldosterone

Question 7

How is Ca2+ reabsorbed in the PCT? TAL? DCT?

Answer 7

1. mainly paracellular with water
   - can be transcellular with Na/Ca anti porter (NCE), and Ca ATPase
2. Paracellular - follows Na
3. TRPV5 and NCE

Question 8

How does Acidemia affect Ca reabsorption?

Answer 8

decreases it by inhibition of TRPV5

*which is on the apical side

Question 9

What channels does PTH up regulate for Ca? Vit D?

Answer 9

1. TRPV5 and NCE

2. TRPV5

Question 10

How is Pi reabsorbed in the PCT? What drives this?

Answer 10

1. Na/Pi sym, its own channel

2. Na/K ATPase

Question 11

What channel does FGF 23 block?

Answer 11

Na/Pi symporter

Question 12

What channels does PTH block for Pi?

Answer 12

Na/Pi symporter and Na/H antiporter on the apical side of PCT cells

Question 13

Acidosis does what to TRP/MV5 channels?

Answer 13

blocks them - acidosis means less Mg/Ca reabsorption

Question 14

What transporters are in alpha cells and where are they?

Answer 14

Apical side: H+ ATPase, K/H antiporter

Basolateral side: HCO3-/CL anti

Question 15

What transporters are in beta cells and where are they?

Answer 15

Apical side: HCO3-/CL anti

Basolateral side: H+ ATPase, K/H antiporter