Here's why:
* Ubiquitous: It's present in all body fluids, including blood, interstitial fluid, and intracellular fluid.
* Efficient: It's highly effective at neutralizing both acids and bases.
* Regulated: The body can adjust the concentration of bicarbonate ions (HCO3-) and carbon dioxide (CO2) to fine-tune the pH.
How it works:
* Carbonic acid (H2CO3) and bicarbonate (HCO3-) act as the buffer pair.
* When acid is added: HCO3- combines with the hydrogen ions (H+) to form carbonic acid (H2CO3).
* When base is added: H2CO3 donates a hydrogen ion (H+) to neutralize the base.
* CO2 is a key player: The body can regulate the concentration of CO2 by changing the rate of breathing. Increased CO2 leads to more carbonic acid formation, lowering pH.
Other important buffer systems:
* Phosphate buffer system: Primarily important in intracellular fluid and the renal system.
* Protein buffer system: Plays a role in both intracellular and extracellular fluid.
While these systems are important, the bicarbonate buffer system is the most significant in maintaining the pH balance within a narrow range, crucial for the proper functioning of all bodily processes.
