RAAS

Question 1

Where does Aldosterone act on the nephron?

Answer 1

collecting duct and later part of distal convoluted tubule

Question 2

What cells does aldosterone act on?

Answer 2

principle cells and alpha intercalated cells

Question 3

what triggers aldosterone?

Answer 3

angiotensin II and high potassium

Question 4

what are the actions of aldosterone?

Answer 4

in the principle cells:

• increase activity of sodium potassium pump to drive more sodium into the blood
• insert potassium channels to release potassium in the urine
• insert sodium channels to remove sodium from the urine and transport it into the blood

in alpha intercalated cells:

• increase activity of proton pump to remove H+ from cell into urine
• increase activity of H+/Na+ pump to remove H+ from the cell into the urine

** acid removed from the blood because the bicarb from CO2 and H2O reaction moves into the blood to neutralise.
aldosterone removes the H+ from this reaction to allow the alpha intercalated cell to work **

Question 5

what is the net effect of aldosterone on the blood?

Answer 5

lose potassium
gain sodium and therefore water
remove acid

main thing is the sodium reabsorption to increase stroke volume to increase BP