RAAS system

Question 1

Juxtaglomerular cells in the kidneys produce and release the hormone renin. What three factors stimulate renin release?

Answer 1

1. Hypotension.
2. Sympathetic nerve cells.
3. Low salt in the distal convoluted tubule.

Question 2

What does renin do to angiotensinogen?

Answer 2

Renin converts angiotensinogen to angiotensin I.

Question 3

Angiotensin I is converted by endothelial cells into angiotensin II. What are the four actions of angiotensin II?

Answer 3

1. Stimulating vasoconstriction of the vasculature.
2. Increasing sodium resorption from the proximal convoluted tubule, which also results in water resorption as a result of osmosis.
3. Triggers the release of ADH from the posterior pituitary gland.
4. Triggers the release of aldosterone from the adrenal cortex.

Question 4

What does aldosterone trigger?

Answer 4

Water retention in the kidneys, and as a result reduced urine production.

Question 5

What are the two consequences of ADH release (anti-diuretic hormone)?

Answer 5

1. Increased water retention/reduced urine production

2. Vasoconstriction of vascular smooth muscle cells.