Renin-Angiotensin-Aldosterone Cascade (E1)

Question 1

Angiotensinogen + Renin =

Answer 1

Angiotensin I

Question 2

Where is renin synthesized and stored?

Answer 2

Juxtaglomerular (JG) cells of the kidney

Question 3

What causes renin to be released from the kidney?

Answer 3

A drop in blood pressure or fluid volume

Question 4

By what 3 mechanisms do JG cells release renin in response to falling arterial pressure?

Answer 4

1) Pressure-sensitive baroreceptors
2) Decreased NaCl delivery to macula-dense cells
3) Increased sympathetic nervous system activity (activates beta-adrenergic receptors)

Question 5

Angiotensin I + Angiotensin-Converting Enzyme (ACE) =

Answer 5

Angiotensin II

Question 6

How does angiotensin II affect blood vessels?

Answer 6

By stimulating vasoconstriction

Question 7

How does angiotensin II act on the adrenal gland?

Answer 7

Angiotensin II stimulates the adrenal gland to release aldosterone

Question 8

How does aldosterone act on the kidneys?

Answer 8

Aldosterone stimulates reabsorption of salt and water

Question 9

How does the RAAS relate to cardiac output?

Answer 9

Normal resting cardiac output is 4-6 L/min. RAAS activation, often driven by decreased blood volume, leads to vasoconstriction and fluid retention, which can increase cardiac output

Question 10

What is the relationship between RAAS and exercise?

Answer 10

Exercise increases the responsiveness of beta-andrenergic receptors, which increases sympathetic nervous system response, a known mechanism for causing JG cells to release renin, allowing the cascade to occur as usual