Biology - Excretory Products and their Elimination Question with Solution | TestHub
Which of the following statements is TRUE ?
Options:
Answer:
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.
