Question

In the ascending limb of the nephron loop (loop of Henle), the:

a.thin segment is not permeable to sodium ions, chloride ions, or water.
b.thick segment is impermeable to water but permeable to sodium and chloride ions.
c.movement of water and solutes is passive.
d.thick segment is permeable to water but impermeable to sodium and chloride ions.

Answer 1

The ascending limb of the nephron loop is impermeable to water but permeable to sodium and chloride ions. The thick segment actively reabsorbs sodium and chloride ions while remaining impermeable to water.

Step-by-step explanation:

The ascending limb of the nephron loop (loop of Henle) is impermeable to water but permeable to sodium and chloride ions. The thick segment of the ascending limb actively reabsorbs sodium and chloride ions through a cotransport system, while remaining impermeable to water due to the absence of aquaporin proteins. This helps in the removal of NaCl and retention of water, leading to a hypoosmotic filtrate by the time it reaches the distal convoluted tubule (DCT) and contributes to the hyperosmotic environment in the kidney medulla.