Lecture 8 Regulation of ECF Volume 2

Question 1

What is the action of Atrial Natriuretic Peptide

Answer 1

Promotes Na+ excretion

Question 2

What is the effect of aldosterone on the distal tubule

Answer 2

Na+ reabsorption

K+ excretion

Question 3

is ANP able to override aldosterone effect

Answer 3

Yes because of volume expansion

Question 4

Patients with Conn’s syndrome (hyperaldosteronism) K+ and Na+ levels will be

Answer 4

Depleted K+

Not hypernatraemic due to ANP = loss of Na+ and H20

Question 5

What happens in the proximal tubule in uncontrolled diabetes

Answer 5

Glucose remains in the tubule as the reabsorption capacity is exceeded
Exerts osmotic effect to retain H2O in the tubule
Na+ reabsorption is decreased
Fluid delivered to ascending loop is less concentrated (water retention)
Interstitial gradient is abolished
The macula densa will detect the high rate of delivery of NaCl so that renin secretion will be suppressed andNa+ reabsorption at the distal tube will be decreased