- Despite its low pKa (6.1) it forms the most important physiological buffer system in the body:
- Relatively high concentrations of bicarbonate in blood
- Forms an ‘open buffer system’ (see above):
- Carbonic anhydrase rapidly converts carbonic acid into constituents
- Both the weak acid and weak base can be independently controlled by the lungs and kidneys respectively
- At normal body pH of 7.4 it is able to buffer acids better than bases
