The osmolarity of the medullary interstitial fluid always equilibrates with the descending limb of the loop of Henle.

Question

Quizplus · Accepted Answer

This is because the descending limb of the loop of Henle is permeable to water but not solutes, so water is able to passively diffuse out of the surrounding medullary interstitial fluid and into the descending limb, leading to an osmotic equilibration between the two.

The Osmolarity of the Medullary Interstitial Fluid Always Equilibrates with the Descending