ANATOMY

Detailed explanation-1: -Water reabsorption is by osmosis through water channels in the membrane. These water channels consist of a family of proteins called aquaporin. At least seven different aquaporin isoforms are expressed in the kidney.

Detailed explanation-2: -Tubular reabsorption occurs when the kidneys reabsorb useful substances, such as glucose, amino acids, and electrolytes, from the filtrate back into the bloodstream.

Detailed explanation-3: -Mechanisms of Reabsorption Namely filtration, reabsorption, secretion, and excretion. Reabsorption in the nephron may be either a passive or active process, and the specific permeability of the each part of the nephron varies considerably in terms of the amount and type of substance reabsorbed.

Detailed explanation-4: -Water reabsorption is a passive process: water is reabsorbed by osmosis. In most of the nephron there is unregulated isosmotic reabsorption of water and solute, in other words, water reabsorption is coupled to solute reabsorption.

Detailed explanation-5: -A large amount of reabsorption occurs in the proximal convoluted tubule. Reabsorption is when water and solutes within the PCT are transported into the bloodstream. In the PCT this process occurs via bulk transport. The solutes and water move from the PCT to the interstitium and then into peritubular capillaries.