RAAS: Renin Angiotensin Aldosterone System

Question 1

Increase in extra cellular fluid effect

Answer 1

Increase glomerular filtration rate b/c more increase of blood flow through the kidneys
And increase SV= increases CO=BP

Question 2

What stimulates the Renin angiotensin aldosterone system?

Answer 2

Reduced blood flow in the kidneys

Question 3

First step in the RAAS is?

Answer 3

The production of renin

Question 4

Renin released from the juxtaglomerular apparatus (JGA) is in response to : list factors

Answer 4

Decrease in the glomerular filtration rate or perfusion pressure (DETECTED BY baroreceptors)
Decrease in NaCl
Innervation from the sympathetic nervous system (na)

Question 5

Renin acts on?

Answer 5

Angiotensinogen to form angiotensin

Question 6

ACE role

Answer 6

Acts on angiotensin 1 to form angiotensin 2

Question 7

Angiotensin 2 role

Answer 7

Acts on the adrenal gland to stimulate release of aldosterone which acts on the kidneys to stimulate absorption of salt (NaCl) and water
Also acts directly on blood vessels, stimulating vasoconstriction (narrowing)

Question 8

Angiotensinogen is?

Answer 8

Protein released from the liver

Question 9

Angiotensin 2 has multiple effects. List some

Answer 9

Increase SV
Increase HR
Increase TPR
Overall increase bp

Question 10

Vasoconstricting effects of angiotensin 2 are mediated via ? What receptor? Explain nature of it

Answer 10

AngII type 1 receptor (AT1 r)
= this is Gq coupled GPCR = PLC- PIP2 into IP3 (Ca 2+ increase-contractile proteins) and DAG (PKC + ion channels )
Stimulates constriction via the same pathway as alpha adrenorceptors but through a different receptor

Question 11

How does angiotensin 2 increase SV via increasing water absorption ?

Answer 11

It increases the activity of NHE on apical membrane of the proximal tubular epithelial cells
This drives increase in sodium reabsorption = increases water reabsorption= increase blood volume= SV

Question 12

Other effects of angiotensin 2

Answer 12

Stimulate aldosterone release
Stimulate vasopressin
Acts directly on blood vessels = vasoconstriction
Increases sodium reabsorption through NHE (pct)

Question 13

Aldosterone acts via what receptors?

Answer 13

Mineralcorticoid receptors

Question 14

Mineralcorticoid receptors are what class of drug targets?

Answer 14

Nuclear receptors (found in the cytoplasm ) = alter protein expression
Increase the expression of ENaC

Question 15

Angiotensinogen 2 effect of stimulating vasopressin

Answer 15

Increases expression of aquaporins to increase water reabsorption
Also stimulates sensation on thirst

Question 16

Vasopressin is released where? Stimulated by?

Answer 16

Released by pituitary
Stimulated by ANGIOTENSIN 2

Question 17

Aldosterone released where.? Stimulated?

Answer 17

in the adrenal glands
Released in response to Angiotensin 2

Question 18

Aldosterone function simplified

Answer 18

Increases ENaC expression to increase sodium reabsorption

Question 19

Renin function simplified

Answer 19

Converts Angiotensinogen to angiotensin 1

Question 20

Renin stimulated? Released?

Answer 20

Stimulated by juxtamedullary apparatus (or JGA)
Released in response to low water/ NaCl
Sympathetic nervous system

Question 21

ACE released from?

Answer 21

Lungs