ANATOMY

Detailed explanation-1: -The proximal tubule also completes the reabsorption of glucose, amino acids, and important anions, including phosphate and citrate, because it is the sole site of transport of these filtered solutes. In addition to solute reabsorption and secretion, the proximal tubule is also a metabolic organ.

Detailed explanation-2: -The main function of the PCT is to reabsorb water and solutes like sodium, which is continuously pumped into the interstitium to create a gradient that allows many other solutes and even water to be reabsorbed by tubule cells.

Detailed explanation-3: -The proximal convoluted tubule avidly reabsorbs filtered glucose into the peritubular capillaries so that it is all reabsorbed by the end of the proximal tubule. The mechanism for glucose reabsorption was described in Chapter 7.4. The proximal tubule is the only site for glucose reabsorption.

Detailed explanation-4: -The major function of the kidney’s proximal convoluted tubules is the reabsorption of filtered water and sodium, a transport largely mediated by conductive Na+ and hydraulic water pathways.

Detailed explanation-5: -Approximately two-thirds of the sodium ions and water and one-hundred percent of the glucose and amino acids is reabsorbed in the proximal convoluted tubule. The reason that so much absorption takes place within this section of the nephron is due to the presence of the brush border (microvili) on the epithelial cells.