Volume Regulation and Diuretics

Question 1

what receptors detect blood pressure?

Answer 1

baroreceptors

Question 2

baroreceptors found where?

Answer 2

atria
right ventricle
pulmonary vasculature
carotid sinus
aortic arch
juxtaglomerular apparatus

Question 3

what is the response to when blood pressure becomes low?

Answer 3

reduced baroreceptor firing > signal through afferent fibres to brainstem > sympathetic activity/ADH release

> JGA cells > renin released

Question 4

what occurs when blood pressure becomes high?

Answer 4

high pressure > atrial stretch > ANP, BNP released

Question 5

ANP is made where?

Answer 5

atria

Question 6

ANP released in response to?

Answer 6

atrial stretch (i.e high blood pressure)

Question 7

actions of ANP

Answer 7

vasodilatation to reduce blood pressure
inhibits the reabsorption of Na+ in PCT + CD
inhibits the release of renin and aldosterone

Question 8

how does ANP reduce blood pressure?

Answer 8

circulates in blood > binds to receptor > stimulates production of cyclic GMP > activates protein kinase G > vasodilation

Question 9

volume expansion leads to?

Answer 9

reduced sympathetic activity, afferent arteriolar dilation and increased GFR, reduce sodium uptake in the PCT and reduce renin- angiotensin and aldosterone (ANP complements this and suppresses ADH)

Question 10

volume contraction leads to?

Answer 10

increased sympathetic activity, renin/angiotensin aldosterone production and increased AVP (ADH) expression > increase sodium reuptake, water retention

Question 11

water reabsorption requires?

Answer 11

osmotic gradient

Question 12

osmotic gradient is generated by?

Answer 12

gradient of interstitial osmolarity

Question 13

example of diuretics?

Answer 13

ACE inhibitor
osmotic diuretics
carbonic anhydrase inhibitors
loop diuretics
thiazides
K+ sparing diuretics
aquaretics

Question 14

mechanism of ACE inhibitor

Answer 14

inhibits angiotensin converting enzyme from converting angiotensin I to angiotensin II

Question 15

vascular effects of ACE inhibitor

Answer 15

vasodilation

Question 16

direct renal effects of ACE inhibitor

Answer 16

decreased Na+ reuptake in PCT

^ Na+ in distal nephron

Question 17

adrenal effects of ACE inhibitor

Answer 17

reduced aldosterone

Question 18

Conceptually the simplest way of increasing osmolarity in the distal nephron is?

Answer 18

adding something that cannot be reabsorbed as the water is removed from the tubular fluid the concentration of the non-reabsorbed substance increases and reduce the difference between the tubular and interstitial osmolarity

Question 19

loop diuretics target what?

Answer 19

triple transporter in the ascending limb of the loop of Henle

Question 20

thiazides target what?

Answer 20

sodium chloride transporter in DCT

Question 21

side effect of thiazides?

Answer 21

increase in Calcium reabsorption

Question 22

potassium sparing diuretic example?

Answer 22

spironolactone

Question 23

action of potassium sparing diuretics

Answer 23

inhibitors of aldosterone function