NEET2026BiologyChapterActual
Which of the following statements is correct regarding the human excretory system?
Options
- AThe ascending limb of the loop of Henle is permeable to water but impermeable to electrolytes.
- BConditional reabsorption of Na^+ and water takes place in the proximal convoluted tubule.
- CVasa recta is absent or highly reduced in cortical nephrons.
- DThe collecting duct is completely impermeable to urea, preventing its entry into the medullary interstitium.
Correct answer
C. Vasa recta is absent or highly reduced in cortical nephrons.
Step-by-step solution
The ascending limb of the loop of Henle is impermeable to water but allows transport of electrolytes actively or passively. Therefore, the first statement is incorrect. Conditional reabsorption of Na^+ and water takes place in the distal convoluted tubule (DCT), not in the proximal convoluted tubule (PCT). Therefore, the second statement is incorrect. In cortical nephrons, the loop of Henle is very short and extends only very little into the medulla. The vasa recta, which is a capillary network running parallel to