On the one hand, a network of neurons in the hindbrain (pons and medulla) regulate the automatic and rhythmic act of breathing. On the other hand, this process is strictly controlled by specific chemoreceptors. There are two types of respiratory chemoreceptors. The arterial chemoreceptors, which monitor and respond to changes in the partial pressure of O2 and CO2 in the arterial blood and the central chemoreceptors in the brain, which respond to changes in the partial pressure of CO2 in their immediate environment.
In addition to respiratory chemoreceptors, receptors in the respiratory muscles and lungs can also influence breathing patterns.