How does the phosphate buffer system help in maintaining the pH of our body?

The phosphate buffer system consists of two ions: dihydrogen phosphate ions and hydrogen phosphate ions. When the number of hydrogen ions in a body's bloodstream increases (pH drops), hydrogen phosphate ions accept hydrogen ions in order to maintain the equilibrium between the concentration of hydrogen and hydroxide ions within the bloodstream. When the number of hydrogen ions in the bloodstream decreases (pH increases), the resulting dihydrogen phosphate ions release hydrogen ions in order to increase the number of hydrogen ions in the blood.