MICROANATOMY

Detailed explanation-1: -The kidneys have two main ways to maintain acid-base balance-their cells reabsorb bicarbonate HCO3− from the urine back to the blood and they secrete hydrogen H+ ions into the urine. By adjusting the amounts reabsorbed and secreted, they balance the bloodstream’s pH.

Detailed explanation-2: -The kidneys produce “new bicarbonate” to do so, and the primary mechanism of new bicarbonate generation involves renal ammonia metabolism.

Detailed explanation-3: -The kidney excretes hydrogen ion through the processes of titratable acid excretion and urinary ammonium excretion1, 2). Quantitatively, urinary ammonium excretion is the primary mechanism of net acid excretion both under basal conditions and in response to acid loads1-3).

Detailed explanation-4: -The bicarbonate buffer system is an acid-base homeostatic mechanism involving the balance of carbonic acid (H2CO3), bicarbonate ion (HCO3-), and carbon dioxide (CO2) in order to maintain pH in the blood and duodenum, among other tissues, to support proper metabolic function.