ANATOMY

Detailed explanation-1: -The solutes and water move from the PCT to the interstitium and then into peritubular capillaries. The reabsorption in the proximal tubule is isosmotic. The proximal tubules reabsorb about 65% of water, sodium, potassium and chloride, 100% of glucose, 100% amino acids, and 85-90% of bicarbonate.

Detailed explanation-2: -The proximal convoluted tubule (see Fig. 11-10A) reabsorbs 65% of the filtered water, Na+, Cl−, and K+. The epithelia of the proximal tubule have “leaky” tight junctions and can maintain only a small transepithelial membrane potential. Most of the energy consumed by the proximal tubule is tied to Na+ reabsorption.

Detailed explanation-3: -The Role of Aquaporins in the Kidneys The majority of water reabsorption that occurs in the nephron is facilitated by the AQPs. Most of the fluid that is filtered at the glomerulus is then reabsorbed in the proximal tubule and the descending limb of the loop of Henle.

Detailed explanation-4: -The majority of solute and water reabsorption occurs in the proximal convoluted tubule. Sodium ions, which are the most plentiful cation (positively charged ion) in the tubular fluid, participate in most solute reabsorption.

Detailed explanation-5: -The Loop of Henle: Concentration. The proximal tubule reabsorbs about 70 percent of the fluid filtered from the blood by the glomerular capillaries.