Electrolyte balance

Question 1

Which cells release renin?

Answer 1

Granular cells of the afferent arteriole

Question 2

What are the 3 main triggers of renin release?

Answer 2

Low afferent arteriole pressure

Activation of sympathetic nerves that supply the JGA

Low NaCl in distal tubule

Question 3

What effect does the RAAS system have on blood pressure?

Answer 3

Increases BP

Question 4

What are the 4 key effects of angiotensin II?

Answer 4

Vasoconstriction

Increased sodium & water reabsorption in kidneys

Aldosterone release

ADH release & increased thirst

Question 5

Which receptor does angiotensin II bind to in the nephron?

Answer 5

AT1

Question 6

How does the binding of angiotensin II to AT1 receptors in the nephron lead to increased sodium reabsorption?

Answer 6

It increases the activity of sodium transporters such as:
- Na+/K+ATPase on the basolateral membrane
- NHE (sodium-hydrogen exchanger) on the apical membrane

Question 7

Aldosterone

• works on which cells?
• binds to which receptor?
• increases numbers of which transporter?

Answer 7

Principal cells

Intracellular mineralocorticoid receptor

ENaC

Question 8

Atrial natriuretic peptide (ANP) is released in response to what?

Answer 8

Increased BP / volume

Question 9

What effect does ANP have on the afferent arteriole, and therefore GFR?

Answer 9

Dilates afferent arteriole - increasing GFR

Question 10

Atrial natriuretic peptide (ANP) has what effect on sodium reabsorption?

Answer 10

Decreases sodium reabsorption