Renal Na+ Excretion

Question 1

What happens in the peritubular capillaries that alter the proximal tubule Na+ reabsorption?

Answer 1

Changes in osmotic pressure and hydrostatic pressure

Question 2

If osmotic and hydrostatic pressure decreases what does this promote?

Answer 2

Na+ and H2O reabsoprtion

Question 3

What is Na+ reabsorption in the PT stimulated by?

Answer 3

RAAS

Question 4

How does the Renin-angiotensin aldosterone system stimulate Na+ reasborption?

Answer 4

Renin converts angiotensin into angiotensin I, which is converted into angiotensin II. Angiotensin II promotes aldosterone release.
Aldosterone increases the Na+ and H2O retention thereby increasing BP

Question 5

What is the action of aldosterone?

Answer 5

stimulates Na+/K+ATPase

Upregulates ENac

Question 6

What happens when renal artery BP increase?

Answer 6

Decrease in the number of Na-H antiporters and red Na+/K+ ATPase activity in PCT
Reduction in Na+ reabsorption in PCT –> Pressure natriuresis
Reduction in H2O reaborption –> Pressure diuresis
ECF volume decreased
Initial BP decreased

Question 7

When ECF volume is low what will be the effect on natiuresis and diuresis?

Answer 7

Small pressure natiuresis and small pressure diuresis