Which part of the nephron is responsible for the reabsorption of water?

The part of the nephron primarily responsible for the reabsorption of water is the loop of Henle and the collecting duct. In the loop of Henle, water is reabsorbed passively in the descending limb, which is permeable to water but not to solutes. As the filtrate moves down this limb, water leaves the filtrate and enters the surrounding interstitial fluid, concentrating the urine.

In the collecting duct, additional water reabsorption occurs, regulated by the hormone vasopressin (also known as antidiuretic hormone, or ADH). When ADH levels are high, the collecting duct becomes more permeable to water, allowing more water to be reabsorbed back into the bloodstream. This mechanism is crucial for maintaining the body's water balance and responding to hydration levels.

Water reabsorption in the proximal convoluted tubule also occurs, but the combination of reabsorption in the loop of Henle and the collecting duct plays a more significant role in the regulation and concentration of urine. The glomerulus is involved in filtration, not in the reabsorption process, while the distal convoluted tubule is involved in the selective reabsorption of ions and some water, but it does not have