What body systems regulate pH?

As far as I know, pH is regulated by the lungs and kidneys. In your blood, pH is represented by C02 + H20 -> H2CO3 -> HCO3- + H+. So, when you exhale rapidly you remove CO2 from your blood. This forces the reaction to favor the reactants and pH increases (Le chatelier's Principle).

As for the kidneys, if the blood pH is too high, then the kidneys will excrete HC03-. If it is too low, it will excrete H+.

Can anyone else think of how pH is regulated?