Why is the bicarbonate buffering system important?

1 Answer
Apr 18, 2014

The bicarbonate buffering system is important in the body because it:

  1. manages the acid and base imbalances produced by both normal and abnormal physiology
  2. assists in the handling of carbon dioxide, the waste product of cellular respiration

The equilibria involved are

CO₂ + H₂O ⇌ H₂CO₃
H₂CO₃ + H₂O ⇌ H₃O⁺+ HCO₃⁻

If there are too many hydronium ions in the blood, the H₃O⁺ will react with bicarbonate to form water and carbonic acid.

If there are too few hydronium ions in the blood, the H₂CO₃ will react to form more H₃O⁺ and HCO₃⁻.

This buffering system works with hyper- or hypoventilation to maintain plasma pH.

In the case of excess acid, hyperventilation increases the loss of CO₂ to the atmosphere. This drives the bicarbonate equilibrium to the left. Plasma acidity decreases.

Hypoventilation decreases the loss of CO₂ to the atmosphere. This drives the bicarbonate equilibrium to the right and increases the acidity.