Your body has a homeostatic regulatory mechanism called the…

Your body has a homeostatic regulatory mechanism called the Carbonic Acid/Carbonate Buffer system, where it uses the ________________________ System to control your blood pH. Chemo-receptors in your carotid artery detect levels of CO2 in the blood, and the higher the dissolved blood CO2, the more acidic your blood is.  It then signals the brain to send a message to which system to increase activity to get rid of the elevated CO2?