The ascending limb of the loop of Henle is where
A)NaCl passively leaves the tubular fluid down its concentration gradient
B)NaCl is actively transported into the interstitial fluid, leaving water behind because the tubular cells are not permeable to water
C)K+ is secreted
D)aldosterone stimulates Na+ reabsorption
E)none of the above occur

Question

Quizplus · Accepted Answer

The ascending limb of the loop of Henle is impermeable to water due to the lack of aquaporins. NaCl is actively transported into the interstitial fluid via the Na+/K+/2Cl- transporter, leaving water behind in the tubular fluid. This process creates a concentration gradient that contributes to the reabsorption of water in the collecting ducts. Choice A is incorrect because NaCl is actively transported, not passively. Choice C is incorrect because K+ secretion occurs in the distal tubule and collecting ducts. Choice D is incorrect because aldosterone acts on the distal tubule and collecting ducts, not the loop of Henle. Choice E is incorrect because an active transport process is occurring in the ascending limb.

The Ascending Limb of the Loop of Henle Is Where