How does the Blood buffer system work?

Buffer systems help to maintain constant plasma pH. There are three buffer systems: Protein buffer system, phosphate buffer system and bicarbonate buffer system. Among these, the bicarbonate buffer system is the most predominant. Buffer Systems function as "shock absorbers" that accept excess H+ ions or OH- ions and keep blood pH constant. For example, if there is an increase in acidity of blood due to excess HCl (a strong acid), then NaHCO3 (Sodium bicarbonate) will buffer it to a weak acid (H2CO3).

HCl+NaHCO3 = NaCl+H2CO3