ANATOMY

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: -Proximal convoluted tubule helps to maintain the pH and the ionic balance of the body fluids.

Detailed explanation-3: -The pH of blood is maintained at   7.4 by the carbonic acid – bicarbonate ion buffering system.

Detailed explanation-4: -H-ion secretion is effected by vacuolar H(+)-ATPase in alpha-intercalated cells and, in K-depleted animals, also by the gastric type H/K ATPase. In animals in alkalosis, beta-intercalated cells secrete bicarbonate by an apical Cl-/HCO3-exchanger, while a basolateral H-ATPase transfers H-ions into the interstitium.

Detailed explanation-5: -So, to get around this limit and hold more hydrogen H+ ions, the urine contains chemical buffers, which bind the hydrogen ions and prevent the pH from dropping too low. The most important is the ammonia buffer system, in which the kidney’s uses a process called ammoniagenesis.