Lecture 20 : Physiology of the Renal System V: Volume Regulation

Question 1

Juxtaglomerular apparatus

Answer 1

Complex of late distal tubule and renal afferent arteriole (from the same nephron)

Question 2

Renin angiotensin system

Answer 2

Increases Na+ absorption from distal tubule and collecting duct

Inhibition :
- Angiotensin-converting enzyme inhibitors
- Renin inhibition
- Aldosterone receptor antagonists

Question 3

angiotensin II actions

Answer 3

Increases Na⁺/H⁺ exchange in proximal tubule → more Na⁺ and water reabsorbed early in the kidney.

Stimulates aldosterone release → increases Na⁺ reabsorption in the distal tubule.

Triggers ADH release → promotes water reabsorption in the kidneys.

Stimulates thirst → encourages fluid intake to increase blood volume.

Question 4

Haemorrhage

Answer 4

Question 5

What happens when afferent arterioles are activated sympathetically

Answer 5

They are activated by noradrenaline, which bind to alpha adrenoreceptors on smooth muscle cells

On granule cells for regulation of renin release, beta adrenoreceptors are the receptors

Question 6

Another stimulus for renin

Answer 6

Question 7

ADH release after haemorrhage

Answer 7

Question 8

Useful diagram

Answer 8

Question 9

Effects of dopamine, prostaglandings and Atrial Natriuretic peptide on ADH release

Answer 9