3.2.2 Respiratory pH regulation

Respiration also has an important regulatory function of the body’s pH. The respiratory function regulates the pH by regulating the CO₂ levels in the blood.

Consider the following chemical equation:

CO₂ + H₂O ⇔H₂CO₃ ⇔ HCO₃^–+ H⁺

If CO₂ in the blood increases, H⁺ increase, because the chemical reaction will tend towards the right in such a situation. This means that the pH decreases. An increase in H+ is detected by the respiratory centre in the brain and breathing increases. An increase in ventilation results in CO₂ being expired and therefore the level in the blood (the pCO₂) decreases. By regulating respiration, the lungs participate in blood pH regulation by increasing or decreasing the respiration rate and the blowing out of CO₂.