Active transport of substances from the blood into the nephron is called _____.The movement of substances from the filtrate back into the blood in the peritubular capillaries is called _____.
tubular secretion; tubular reabsorption
Tubular secretion is the transfer of materials from peritubular capillaries to the renal tubular lumen and occurs mainly by active transport. It is the tubular secretion of H+ and NH4+ from the blood into the tubular fluid that helps to keep blood pH at its normal level.