RAAS System

Question 1

Effective arterial blood volume can be defined as?

Answer 1

The part of arterial circulation that is responsible for organ perfusion

Question 2

IF Effective arterial blood volume goes down, what occurs at the kidney?

Answer 2

The kidneys RETAIN sodium and water

Question 3

Effective arterial blood volume is sensed where in the body?

Answer 3

Carotid sinus, aortic arch, LV, and the juxtaglomerular apparatus in the kidney

Question 4

Effective arterial blood volume can be reduced by what factors?

Answer 4

• Reduced actual arterial blood volume (i.e. hemorrhage, dehydration)
• Increased vascular capacitance (cirrhosis, sepsis)
• Reduced cardiac output (congestive heart failure)

Question 5

Renin is a proteolytic enzyme made by the __

Answer 5

kidney

Question 6

Renin coverts __ to __

Answer 6

angiotensinogen to angiotensin 1

Question 7

Renin helps initiates a cascade that __

Answer 7

supports blood pressure and defends circulating blood volume

Question 8

Juxtaglomerular cells are what type of cells and where are they located specifically within the kidney?

Answer 8

smooth muscle cells; located in the media of the afferent arteriole

Question 9

Decreased effective circulating volume leads to

Answer 9

• decreased cholorine in tubule at macula densa
• stimulation of baroreceptors leading to increased sympathetic tone (high pressure: carotid sinus, aortic arch, afferent arteriole. Low pressure: Central veins, atria)

Both lead to increased renin release into systemic circulation

Question 10

Peptides derived from angiotensinogen are produced from the __

Answer 10

liver

Question 11

List the key steps in the RAAS System

Answer 11

1. Angiotensinogen is cleaved by renin into angiotensin 1
2. Inactive Angiotensin 1 is cleaved by ACE into active angiotensin II
3. Angiotensin II binds to receptors etc.

Note: ACE break down bradykinin into inactive metabolites

Question 12

What is the role of angiotensin II?

Answer 12

Most of its effect on the vasculature and transport functions are mediated by AT1 receptors. It stimulates aldosterone release from zona glomerulosa of adrenal gland

Question 13

What are the physiologic effects of angiotensin II?

Answer 13

• arteriolar vasoconstriction

- sodium and water retention

Question 14

ACE is found where? What does it do?

Answer 14

endothelial cells; catalyzes AI to AII OR converts bradykinin to inactive metabolites

Question 15

Most individuals with primary hypertension have elevated levels of which protein?

Answer 15

renin

Question 16

Low renin hypertension =

Answer 16

good response to diuretics and CCBs

Question 17

How does CKD affect the RAAS system?

Answer 17

Increased renin and aldosterone

Question 18

How does renal artery stenosis affect the RAAS system?

Answer 18

increased renin and aldosterone

Question 19

How does primary aldosteronism affect the RAAS system?

Answer 19

Decreased renin and increased aldosterone

Question 20

How is the RAAS system affect in congestive heart failure?

Answer 20

• Decreased cardiac output and peripheral cascular resistsance leads to decreased effective arterial blood volume
• Decreased EABV leads to increased renal sodium retention
• Increased renal sodium retention leads to increased venous pressure
• Increased venous pressure leads to edema

Question 21

RAAS is activated by a decrease or increase in EABV?

Answer 21

Decrease