What happens to water in the descending limb of the loop of Henle?

• A. Water is secreted into the tubular fluid.
• B. Water remains unchanged in the tubular fluid.
• C. Water is reabsorbed into the bloodstream.
• D. Water is actively transported out of the nephron.

Answer: (C)

Verified step by step guidance

1. Understand the function of the loop of Henle in the nephron, which is to concentrate urine and conserve water.
2. Recognize that the descending limb of the loop of Henle is permeable to water but not to solutes.
3. Know that as the tubular fluid descends, the surrounding interstitial fluid in the renal medulla becomes increasingly hypertonic.
4. Realize that due to the osmotic gradient, water moves out of the descending limb into the interstitial fluid and then into the bloodstream.
5. Conclude that water is reabsorbed from the descending limb into the bloodstream, concentrating the tubular fluid.