14: Renal Transport Mechanisms

Question 1

Where does most reabsoprtion occur?

Answer 1

Proximal tubule

Question 2

NKCC2 channel electric charge

Answer 2

Electrically neutral bc of 1 Na, 1 K, and 2 Cls

Question 3

Principal cells: Reabsorb and secrete what?

Answer 3

Reabsorb: Na, H2O
Secrete: K

Question 4

A-intercalated cells: reabsorb and secrete what?

Answer 4

Reabsorb: K, HCO3
Secrete: H

Question 5

B-intercalated cells: reabsorb and secrete what?

Answer 5

Reabsorb: H, Cl
Secrete: HCO3, K

Question 6

Two things that stimulate ADH secretion and which one is more important

Answer 6

Hyperosmolarity (more important), volume depletion

Question 7

Where are osmoreceptors for ADH?

Answer 7

Hypothalamus and liver

Question 8

Kidney interstitium location

Answer 8

Between tubules, glomeruli and vessels

Question 9

What is found in kidney interstitium

Answer 9

Fibroblasts, ECM, interstitial fluid

Question 10

What substances play the biggest roles in medullary osmolarity?

Answer 10

NaCl and urea

Question 11

Diuresis

Answer 11

Continually Reabsorbing solutes and fail to reabsorb water -> lots of dilute urine

Question 12

Why does cortical CD have higher concentration of urea? What is the function of this?

Answer 12

Distal tubule is impermeable to it -> urea builds up and passively diffuses out of CD into medullary interstitium to contribute to hyperosmolarity

Question 13

Natriuresis

Answer 13

Excretion of an excess amount of Na in the urine

Question 14

Causes of natriuresis

Answer 14

Drugs, Hormones (ANP), high renal perfusion pressure