The portion of the nephron tubule that is essentially always impermeable to water is the:
A)proximal tubule.
B)distal tubule.
C)collecting tubule.
D)ascending nephron loop.

Question

Quizplus · Accepted Answer

The ascending nephron loop of Henle is impermeable to water. This is because it lacks aquaporins on its apical membrane, which are the transport channels responsible for water reabsorption in the nephron. Instead, the ascending limb actively pumps out sodium and chloride ions, which creates an osmotic gradient that enables water to be reabsorbed in the collecting duct later on.

The Portion of the Nephron Tubule That Is Essentially Always