RAAS pathway

Question 1

Role of each RAAS component

Answer 1

Renin - secreted by the juxtaglomerular apparatus in the kidney when renal blood flow/pressure OR sodium levels in filtrate is reduced OR sympathetic nervous system innervation
–> converts angiotensinogen into angiotensin 1
Angiotensin 1 - inactive molecule
ACE inhibitor - converts A1 into A2
Angiotensin 2 - promotes vasodilation and aldosterone secretion (agonist at angiotensin 2 type 1 receptor and angiotensin 2 type 2 receptor)
Aldosterone - secreted by adrenal cortex –> increases sodium retention -> increased water retention

Question 2

What part of the nephron does aldosterone act on?

Answer 2

distal tubule and collecting duct

Question 3

What is ACE also referred to and why?

Answer 3

Kinase 2 because it breakdown bradykinin into inactive products

Question 4

How does RAAS promote electrolyte regulation

Answer 4

A2 –> aldosterone which enables:
- sodium reabsorption –> water retention
- potassium secretion into filtrate