AP BIOLOGY

Detailed explanation-1: -The tubular secretion of H+ and NH4+ from the blood into the tubular fluid is involved in blood pH regulation. The movement of these ions also helps to conserve sodium bicarbonate (NaHCO3).

Detailed explanation-2: -The materials that are exuded into the tubular fluid for exclusion from the body include Potassium ions (K+), Hydrogen ions (H+), Ammonium ions (NH+), Creatinine, and Urea.

Detailed explanation-3: -In the convoluted distal tubule (early distal tubule), most H-ion secretion occurs by means of the Na+/H+ exchanger.

Detailed explanation-4: -A Luminal H+ ATPase then secretes the newly generated H+ into the tubular lumen via primary active transport. The newly generated HCO3-molecule is transported past the basolateral membrane and into the extracellular fluid through a bicarbonate porter.

Detailed explanation-5: -Primary active secretion of H+ occurs in a special type of cell called the intercalated cells of the late distal tubule and in the collecting tubules.