Question

As urine moves through the descending loop of Henle, which of the following is true?

A. Sodium is reabsorbed into the bloodstream.
B. Sodium is secreted into the loop of Henle.
C. Water is reabsorbed into the bloodstream.
D. Water is secreted into the loop of Henle.
E. Potassium is reabsorbed into the bloodstream.

Answer 1

Water is reabsorbed from the filtrate to the bloodstream in the descending loop of Henle due to the osmotic gradient, leading to an increase in the filtrate's osmolality.

Step-by-step explanation:

As urine moves through the descending loop of Henle, the correct statement is that water is reabsorbed into the bloodstream. The descending limb of the loop of Henle is permeable to water, which means that water can move out of the filtrate and into the interstitial fluid, leading to an increase in osmolality inside the loop as it descends. This process happens because of the osmotic gradient between the filtrate and the surrounding interstitial fluid. Sodium, on the other hand, is not reabsorbed in the descending limb; it is reabsorbed further along in the ascending limb of the loop of Henle.