Diuretics

Question 1

How do carbonic anhydrase inhibitors act as a diuretic.

Answer 1

Act in PCT. H2CO3 can’t dissociate into H+ and HCO3-. This downregulated Na H transporter. Less Na on apical membrane entering cell meaning less water is absorbed.

Question 2

Describe how osmotic diuretics work?

Answer 2

Expands ECV by exerting an osmotic effect making blood less viscous. Inhibits renin release increasing renal blood flow.

Question 3

What are the sIde effects of osmotic diuretics like mannitol?

Answer 3

Increased circulating volume exacerbating heart failure leading to pulmonary oedema. Dehydration and hypernatraemia if used in excess.

Question 4

How does a loop diuretic like furosemide work?

Answer 4

Blocks NaK2Cl transporter in the thick descending loop of Henle. Less Na can be reabsorbed therefore less water

Question 5

Describe how thiazides work as diuretics?

Answer 5

Blocks Na Cl cotransporter in DCT.

Question 6

Describe the action of potassium sparing diuretics like amiloride?

Answer 6

Blocks ENAC channels in DCT and CD

Question 7

What effect would increased plasma conc of K have on collecting duct?

Answer 7

Increased secretion of Aldosterone which increases rom k channels allowing more to be excreted