Question

Through the thick segment of ascending limb of Henle’s loop the

• A. NaCl can pass by active transport from filtrate to the interstitial fluid.
• B. NaCl can pass by passive transport into interstitial fluid.
• C. NaCl cannot pass from the filtrate to interstitial fluid.
• D. Water can pass freely from filtrate to interstitial fluid.

Answer 1

Answer: (A)

The ascending limb of loop of Henle has a thin and a thick segment. The thin ascending limb is found in the medulla of the kidney, and the thick ascending limb can be divided into a part that is in the renal medulla and a part that is in the renal cortex. Through the thick segment of ascending limb of loop of Henle, the $NaCl$ can pass by active transport from the filtrate to the interstitial fluid. The medullary ascending limb remains impermeable to water. Sodium, potassium $\left(K^{+}\right)$and chloride $\left(C{l}^{-}\right)$ions are reabsorbed by active transport. $K^{+}$is passively transported along its concentration gradient through a $K^{+}$leak channel in the apical aspect of the cells, back into the lumen of the ascending limb,