Question

What does secretion is refered to in function of kidney? What is actually the meaning of secretion in function of kidney ? How does it takes place?

Answer 1

Secretion is the movement of material from one point to another. Tubular secretion in nephrons (the structural and functional unit of kidney) is the transfer of materials from peritubular capillaries (tiny blood vessels, supplied by the efferent arteriole, that travel alongside nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron) to renal tubular lumen. Tubular secretion is caused mainly by active transport. These substances are present in great excess, or are natural poisons. Tubular secretion occurs from the epithelial cells that line the renal tubules and collecting ducts. It is the tubular secretion of H⁺ and NH₄⁺ from the blood into the tubular fluid (i.e. urine - which is then excreted from the body via the ureter, bladder and urethra) that helps to keep blood pH at its normal level.