NEETZoologyExcretory Products and their Elimination
A fall in glomerular blood flow or blood pressure activates compensatory mechanisms in the body. Which of the following correctly identifies a regulatory chemical involved, its specific target site in the nephron, and its physiological action?
Options
- AADH Proximal convoluted tubule Obligatory reabsorption of water
- BAldosterone Distal convoluted tubule Conditional reabsorption of Na ⁺ and water
- CRenin Ascending limb of loop of Henle Active transport of NaCl
- DANF Collecting duct Increased reabsorption of water and Na ⁺
Correct answer
B. Aldosterone Distal convoluted tubule Conditional reabsorption of Na ⁺ and water
Step-by-step solution
A fall in glomerular blood pressure activates the Juxtaglomerular cells to release renin, which ultimately leads to the formation of Angiotensin II. Angiotensin II stimulates the adrenal cortex to release aldosterone. Aldosterone acts on the distal convoluted tubule (DCT) and causes conditional reabsorption of Na ⁺ and water, which helps in increasing blood pressure. The other options are incorrect because: ADH acts on the latter parts of the tubule (DCT and collecting duct), not the proximal convoluted tubule (PCT