The Kidney: Lectures 1-3 (Forgetting unit lecture number)

Question 1

What is counter transport?

Answer 1

When one transport protein channel transports two molecules simultaneously in opposite directions

Question 2

Describe the reabsorption of Na+ from the proximal tubule to tubule cells

Answer 2

• Na+ counter transported with protons

Question 3

Describe the reabsorption of Na+ from the proximal convoluted tubule cells to the interstitial fluid

Answer 3

Na+ is pumped by Na+/K+ ATPase

K+ is recycled by a K+ ion channel

Question 4

What unique transporter is involved in the Loop of Henle? What does it transport?

Answer 4

Na-K-Cl co transporter (NKCC)

Cotransports Na+ K+ and 2Cl-

Question 5

Describe the reabsorption of Na+ in the loop of Henle tubules to tubule cells

Answer 5

NKCC cotransports Na+ into the tubule cells

K+ is recycled by a K+ ion channel

Question 6

Describe the reabsorption of Na+ from the loop of Henle tubule cells to the interstitial space

Answer 6

Na+ is pumped by Na+/K+ ATPase into the interstitial space

K+ is recycled by a K+ ion channel
2Cl- absorbed via an ion channel

Question 7

Describe how reabsorption occurs in the collecting duct

Answer 7

Ion channels for Na+ and K+ between tubal and tubule cells

Na+ pumped across tubule cell to interstitial space by Na+/K+ ATPase

K+ channel recycles K+ from tubule cell to tubule

Question 8

What is Aldosterone?

Answer 8

A steroid hormone that increases the expression of ion channels and Na+/K+ ATPase

Question 9

Where does aldosterone act?

Answer 9

In collecting duct tubule cells

Question 10

What is the overall effect of increased aldosterone concentration?

Answer 10

Increased Na+ reabsorption

Question 11

Why is the effect of aldosterone only apparent after a few hours?

Answer 11

Aldosterone initiates the increased synthesis of the proteins involved in Na+/K+ ATPase and ion channels thus time is required for the proteins to be synthesised