SS3. Aldosterone

Question 1

Where does Aldosterone come from?

Answer 1

The adrenal gland, found above the kidney.

Question 2

What else helps in creating aldosterone?

Answer 2

Cholesterol, found in cortex cells.

Question 3

What are triggers of producing aldosterone?

Answer 3

1) Noticing angiotensin 2

2) K+ in blood. If there’s too much, K+ triggers the adrenal gland to put aldosterone in the blood.

Question 4

Where does aldosterone work on, which tubules?

Answer 4

Late distal convoluted tubule
Collecting duct
the principal cells with peritubular capillary, with basolateral surface between principal cell and peritubular capillary and apical between principal cell and duct.

Question 5

What does the Principal cell have, and what does the peritubular capillary have a lot of?

Answer 5

Principal cell: lot of K+

Peritubular capillary: Na+

Question 6

What does aldosterone do in the cell?

Answer 6

1) Drives Na/k ATPase pump to work harder
2) Adds K+ channels on apical surface. K+ inside principal cell move into tubule with filtrate, so blood is losing K+ (which you want)
3) Adds Na+ channels. Na moves into cell (down gradient) and into blood. So gain NA+, H2O is pulled into blood, too.

Question 7

What does losing K+ and gain Na+ and water result into, with help of Aldosterone?

Answer 7

Gain of Na+ and H2o results in increased stroke volume and thereby blood pressure

Question 8

What other type of cells does aldosterone work on? Why is it used?

Answer 8

Alpha-intercalated cells. This removes protons that represent acid.

Question 9

What can be found next to the alpha intercalated cells?

Answer 9

The peritubular capillary, with basolateral and apical surface.

Question 10

What happens when the blood gets too acidic (too much H+ aka protons)?

Answer 10

1) All cells make CO2 + H2O. Carbonic anhydrase helps CO2 and H2O form H+ and HCO3- (bicarb) inside the alpha-intercalated cells.
2) HCO3- is transported into blood, to neutralise protons. Cl- is transported into the cell.
3) HCO3- binds H+, results in H2O and CO2.
4) Cl- can go back to blood via channel, but there’s still proton inside alpha-intercalated cells. –> H+ moved out via channel with use of ATP, works with help of aldosterone
4) Another channel that moves H+ into urine –> Cells have a lot of K+. Na+ wants to move in bc of the K+ in the cell, which allows H+ to move out the cell. Also driven by Aldostetrone.
5) Another transporter helps H+ into urine -> K+ transported int o cell (takes energy bc it forced into cell
6) OR Na/K pump. 2K+ in, 3Na uit, takes energy.

Question 11

What is the key concept of getting rid of acid in blood?

Answer 11

Create more protons inside alpha-intercalated cell and dumping them into the urine via ATP pump.