The ion pumps in the ascending limb of the loop of Henle can maintain an osmotic difference of 400 mOsm across the wall of the tubule.

Question

Quizplus · Accepted Answer

The ion pumps in the ascending limb of the loop of Henle actively transport ions out of the tubule, contributing to the osmotic gradient in the medulla, but they do not directly maintain a 400 mOsm difference across the tubule wall. The osmotic gradient in the kidney medulla can reach up to 1200 mOsm/L due to the cumulative effect of ion transport, urea recycling, and water reabsorption along different parts of the nephron, not just the ascending limb.

The Ion Pumps in the Ascending Limb of the Loop