<P> The bicarbonate buffer system is an acid - base homeostatic mechanism involving the balance of carbonic acid (H CO), bicarbonate ion (HCO), 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) 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) so that any excess acid or base introduced to the system is neutralized . </P> <P> Failure of this system to function properly results in acid - base imbalance, such as acidemia (pH <7.35) and alkalemia (pH> 7.45) in the blood . </P>

Describe the blood hydrogen carbonate buffer system. what happens when blood acidity rises