Where do chemorecptors signal to increase the breathing rate?

Chemoreceptors that signal to increase the breathing rate primarily reside in the carotid bodies and the medulla oblongata. When they detect elevated levels of carbon dioxide (CO2) or decreased levels of oxygen (O2) in the blood, they send signals to the respiratory centers in the brainstem. This stimulation leads to an increased rate and depth of breathing to enhance gas exchange and restore normal levels of O2 and CO2 in the bloodstream.