Which of the following statements about the loop of Henle of juxtamedullary nephrons is correct? A) The ascending limb of the loop of Henle is freely permeable to H₂O and NaCl. B) The filtrate is isotonic as it enters the loop of Henle, hypertonic at the tip of the loop, and hypotonic as it leaves the loop of Henle. C) The descending limb of the loop of Henle actively transports NaCl out of the tubule into the interstitial fluid. D) All of these. E) None of these.

Question

Quizplus · Accepted Answer

The descending limb of the loop of Henle is freely permeable to water, but not to salts. Therefore, as water leaves the descending limb, the filtrate becomes increasingly concentrated with salts, making it hypertonic at the tip of the loop. As the filtrate moves up the ascending limb, NaCl is actively transported out of the tubule into the interstitial fluid, making the filtrate more dilute. Therefore, the correct statement is that the filtrate is isotonic as it enters the loop of Henle, hypertonic at the tip of the loop, and hypotonic as it leaves the loop of Henle.

Which of the Following Statements About the Loop of Henle