Q58 / 200 · MHT CET - Medical 2026 (24 April Shift 2) · Biology
Which of the following statements is TRUE ?
- AAs tubular fluid passes down through descending limb of loop of Henle, it's osmolarity decreases.
- BAs tubular fluid flows up through the ascending limb of the loop of Henle, it's osmolarity increases.
- Correct answerCAs blood passes through descending limb of the vasa recta, it's osmolarity increases.
- DAs blood flows through the ascending part of the vasa recta, it becomes hyper osmotic.
Solution
The descending limb of the loop of Henle is permeable to water but almost impermeable to electrolytes. As tubular fluid passes down, water moves out into the interstitium, causing the osmolarity of the fluid to increase.
The ascending limb of the loop of Henle is impermeable to water but allows the transport of electrolytes. As tubular fluid flows up, electrolytes move out, causing the osmolarity of the fluid to decrease.
The vasa recta acts as a counter-current exchanger. As blood passes through the descending limb of the vasa recta, it enters the hyperosmolar medullary interstitium. Water leaves the blood and solutes (NaCl and urea) enter, causing the osmolarity of the blood to increase.
As blood flows through the ascending part of the vasa recta, solutes leave the blood and water enters, causing the osmolarity to decrease back towards normal levels.
Answer: As blood passes through descending limb of the vasa recta, it's osmolarity increases.
The ascending limb of the loop of Henle is impermeable to water but allows the transport of electrolytes. As tubular fluid flows up, electrolytes move out, causing the osmolarity of the fluid to decrease.
The vasa recta acts as a counter-current exchanger. As blood passes through the descending limb of the vasa recta, it enters the hyperosmolar medullary interstitium. Water leaves the blood and solutes (NaCl and urea) enter, causing the osmolarity of the blood to increase.
As blood flows through the ascending part of the vasa recta, solutes leave the blood and water enters, causing the osmolarity to decrease back towards normal levels.
Answer: As blood passes through descending limb of the vasa recta, it's osmolarity increases.
Hence, the correct answer is option: 'C'.