Question
Match each diuretic in Column A with its corresponding site of action in Column B.
|
Column A
|
Column B
|
|
A. Acetazolamide
B. Torsemide
C. Chlorthalidone
D. Vasopressin
|
-
Thick ascending loop of Henle
-
Collecting duct
-
Distal convoluted tubule
-
Proximal convoluted tubule
|
| A. |
A-2, B-3, C-1, D-4
|
| B. |
A-3, B-4, C-2, D-1
|
| C. |
A-1, B-2, C-4, D-3
|
| D. |
A-4, B-1, C-3, D-2
|
Show Answer
|
Correct Answer » D
Explanation
|
|
1. Acetazolamide: This is a carbonic anhydrase inhibitor that works in the proximal convoluted tubule of the nephron to inhibit the reabsorption of bicarbonate ions.
This results in a mild diuretic effect and the excretion of excess fluids and electrolytes.
2. Torsemide: This is a loop diuretic that works in the thick ascending limb of the loop of Henle to inhibit the reabsorption of sodium, potassium, and chloride ions.
By blocking the Na+/K+/2Cl- cotransporter, torsemide decreases the amount of ions that are reabsorbed into the bloodstream and increases the amount of ions that are excreted in the urine. This results in a more potent diuretic effect than acetazolamide.
3. Chlorthalidone: This is a thiazide-like diuretic that works in the distal convoluted tubule to inhibit the reabsorption of sodium ions.
By blocking the Na+/Cl- cotransporter, chlorthalidone decreases the amount of sodium that is reabsorbed into the bloodstream and increases the amount of sodium that is excreted in the urine. This results in a moderate diuretic effect.
4. Vasopressin: This is not a diuretic, but rather an antidiuretic hormone (ADH) that works in the collecting duct to increase water reabsorption.
Vasopressin acts on the V2 receptor in the collecting duct to stimulate the insertion of aquaporin-2 channels into the apical membrane, which allows for the reabsorption of water. This results in a decrease in urine volume and an increase in urine concentration.
