<P> The bicarbonate buffer system is an acid - base homeostatic mechanism involving the balance of carbonic acid (H CO), bicarbonate ion (HCO − 3), and carbon dioxide (CO) in order to maintain pH in the blood and duodenum, among other tissues, to support proper metabolic function . Catalyzed by carbonic anhydrase, carbon dioxide (CO) reacts with water (H O) to form carbonic acid (H CO), which in turn rapidly dissociates to form a bicarbonate ion (HCO − 3) and a hydrogen ion (H) as shown in the following reaction: </P> <P> As with any buffer system, the pH is balanced by the presence of both a weak acid (for example, H CO) and its conjugate base (for example, HCO − 3) so that any excess acid or base introduced to the system is neutralized . </P>

What is the main buffer system in human blood