During reabsorption, sodium ions cross the proximal tubule walls into the interstitial fluid principally by means of
A) bulk flow.
B) active transport.
C) countercurrent multiplication.
D) phagocytosis.
E) endocytosis.

Question

Quizplus · Accepted Answer

Sodium ions are reabsorbed from the proximal tubule into the interstitial fluid primarily through active transport, which involves the use of energy to move sodium ions against their concentration gradient.

During Reabsorption, Sodium Ions Cross the Proximal Tubule Walls into the Interstitial