What is the Role of Kidney in Acid Base Balance?

Answer: Kidneys regulate acid-base balance by primarily excreting hydrogen ions (H+ ions) and reabsorbing bicarbonate ions (HCO3-), thereby maintaining blood pH levels.

The kidneys play a crucial role in maintaining the acid-base balance of the body by:

1. Excretion of Hydrogen Ions: The kidneys excrete excess hydrogen ions (H+) in the urine, directly influencing the body’s pH balance.
2. Bicarbonate Reabsorption: They reabsorb bicarbonate (HCO3-) from the urine, which is a key buffer in the blood, helping to neutralize acids.
3. Production of Bicarbonate: In response to acidosis (excess acidity), the kidneys can produce new bicarbonate ions, adding to the blood’s buffering capacity.
4. Ammonia Production: Kidneys produce ammonia from the metabolism of amino acids, which bind to excess H+ ions, facilitating their excretion and maintaining acid-base equilibrium.
5. Phosphate Buffer System: The kidneys use the phosphate buffer system in urine, where hydrogen ions can bind to phosphate ions, forming phosphoric acid. This helps with buffering excess acid in the urine and facilitates some acid excretion.
6. Acid-Base Balance Regulation: Through these mechanisms, the kidneys adjust the blood’s pH by either removing or conserving acids and bases, maintaining acid-base homeostasis.

Also, check out our easy-to-read article on the Kidney, if you want to learn more.