PCT is lined by simple cuboidal brush border epithelium. Brush border increases the surface area for

reabsorption.

Functions of PCT:

$1.$ PCT absorbs almost all essential nutrients.

$2.$ PCT absorbs about 70-80 % electrolytes and water.

$3.$ As PCT selectively secretes ${\mathrm{H}}^{+}$ ions, ammonia and potassium ions into the filtrate and also absorbs ${\mathrm{H}\mathrm{C}\mathrm{O}}_3^{-}$ from it, it maintains the pH and ionic balance of the body fluids. The maximum reabsorption (65 to 70%) takes place in proximal convoluted tubule of the nephron.