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 and 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.