The descending arm of the loop of Henle is permeable to ____ but impermeable to ____.
A) water; potassium ions
B) water; sodium ions
C) sodium ions; water
D) potassium ions; water
E) all choices are incorrect

Question

The descending arm of the loop of Henle is permeable to ____ but impermeable to ____.
A) ​water; potassium ions
B) ​water; sodium ions
C) ​sodium ions; water
D) ​potassium ions; water
E) ​all choices are incorrect

Quizplus · Accepted Answer

The descending arm of the loop of Henle is permeable to water but impermeable to sodium ions. This allows for the passive reabsorption of water, which is crucial in the process of urine concentration. Sodium ions are actively transported out of the ascending limb of the loop of Henle, contributing to the formation of a concentration gradient that drives the reabsorption of water in the descending limb. Potassium ions are also actively transported in the ascending limb, but they are not involved in the permeability of the descending limb.

The Descending Arm of the Loop of Henle Is Permeable