GENERAL HISTOLOGY

Detailed explanation-1: -While much of the reabsorption and secretion occur passively based on concentration gradients, the amount of water that is reabsorbed or lost is tightly regulated. This control is exerted directly by ADH and aldosterone, and indirectly by renin. Most water is recovered in the PCT, loop of Henle, and DCT.

Detailed explanation-2: -Sodium absorption varies widely under conditions of Na+ excess or depletion and is primarily regulated by the hormones aldosterone and vasopressin, both of which increase renal Na+ absorption by acting on the principal cells of the kidney.