*Role of Kidney in Regulation

Question 0

MAP=

Answer 0

CO x SVR (TPR)

Question 1

mean circulatory pressure takes into account:

Answer 1

blood volume and cardiovascular capacitance

Question 2

what is needed to generate natriuresis from high renal blood flow?

Answer 2

the capsule

Question 3

changes in blood flow to which area of the kidney result in natriuresis?

Answer 3

inner medulla

Question 4

fraction of adult population that is salt sensitive over 60

Answer 4

30%, 70-80%

Question 5

what are effective treatments for hypertension?

Answer 5

• correction of underlying cause
• diuretics (remove excess fluid), vasodilators (dec TPR)– but both activate RAAS and cause volume retention
• renal transplant

Question 6

What turns on RAAS?

Does it shift RFC?

Answer 6

• Salt & volume depletion turns on RAAS
• shift RFC right

Question 7

What turns off RAAS? Does this cause RFC shift?

Answer 7

Salt loading turns off RAAS

shift left

Question 8

In a normal person sodium intake can vary a lot and kidney can still maintain BP within a narrow range becasue …..

Answer 8

Becuase of the renin angiotensin systen (RAAS)

For a normal person renal funcion curve looks like a verticle line

Question 9

RAAS is activated in response to …

Answer 9

decreased blood flow to the kidney (in experiment renal artery was clipped/blocked)

Question 10

Both ___ and ___ can cause hypertention

Answer 10

inceased volume and angiotensin II

Question 11

how does essential hypertension appear on a RFC?

Answer 11

• Right shifted from the normal RFC, and flatter if salt-sensitive (small changes in sodium result in larger changes in BP = flatter curve).

Question 12

Salt sensative hypertension appears ____ on RFC, which means ____

Answer 12

flatter curve means small changes in sodium result in larger changes in BP

Question 13

would a patient with primary/essential hypertension have volume overload?

Answer 13

• no measurable volume overload (corrected by autoregulation)
• volume overload tells us there is a subtle defect in sodium excretion, because a normal kidney excretes a sodium and water to maintain normal BP

Question 14

In PRIMARY hypertention, volume overload tells us ___, because ___

Answer 14

there is a subtle defect in sodium excretion, because a normal kidney excretes enough sodium and water to maintain normal BP

Question 15

Blocking Ang II causes a _____ shift of the renal function curve and thus ____ BP

Answer 15

Blocking AngII – left shift, lower BP (Ang II’s job is to increase BP)

Question 16

Giving excess Ang II ___ shift of renal function curve (RFC) with ______ BP.

Answer 16

excess Ang II = right shift, higher BP.

Question 17

The Renin-Angiotensin-Aldosterone System (RAAS)

Answer 17

• Decreased BP (hemorrhage, standing) cause increased renin secretion by the kidneys.
• Renin converts angiotensinogen to Ang I, which is converted by ACE to Ang II.
• Overall effect: increased salt/water retention to INCREASE BP

Question 18

In the kidney what senses inc in systemic BP?

Answer 18

Medualry Blood flow is increased if systemic BP is high. Renal capsule senses adn responds to this by increasing natriuresis.

After a while, medullary vasoconstriction decreases flow to the medulla, which decreases natriuresis.

Question 19

Natriuresis:

Answer 19

excretion of large amounts of sodium in urine; similar to diuresis (excretion of large quantity of urine), except in natriuresis urine is very salty