MEDICAL PHYSIOLOGY

Detailed explanation-1: -The thin descending limb, like the proximal tubule, is highly permeable for water (the channels are of aquaporin 1), whereas, beginning exactly at the turning point, the thin ascending limb is impermeable for water.

Detailed explanation-2: -In summary, the loop of Henle is surrounded by tissue fluid which has a high concentration of ions in it. This causes water to move out of the descending limb by osmosis. This produces a more concentrated filtrate because of this, ions move out of the loop in the thin ascending limb.

Detailed explanation-3: -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-4: -The thick ascending limb of Henle’s loop actively reabsorbs sodium chloride (NaCl) but is impermeable to water. Therefore this segment raises the osmolality of the interstitial fluid, thus generating medullary interstitial hypertonicity and a lumen-to-interstitium osmotic gradient.