AP BIOLOGY

Detailed explanation-1: -Ascending limb of loop of Henle is impermeable to water. Here water is not reabsorbed, rather sodium, potassium, magnesium and chloride are reabsorbed and therefore the filtrate becomes hypotonic to blood plasma.

Detailed explanation-2: -The descending loop of Henle is impermeable to water.

Detailed explanation-3: -The ascending limb of the nephron loop is impermeable to water, but Na + and Cl – are pumped out into the surrounding fluids by active transport. As fluid travels up the ascending limb, it becomes less and less concentrated because Na + and Cl – are pumped out.

Detailed explanation-4: -The ascending limb of the loop of Henle is a direct continuation from the descending limb of loop of Henle, and one of the structures in the nephron of the kidney. The ascending limb has a thin and a thick segment. The ascending limb drains urine into the distal convoluted tubule.

Detailed explanation-5: -The thin ascending limb is impermeable to water, due to it having no aquaporin channels. Na+ reabsorption occurs passively through epithelial Na+ (eNaC) channels and Chloride (Cl-) ions are reabsorbed in the thin ascending limb through Cl-channels.