Respiratory drive, or respiratory control, refers to the process by which detected changes in the body's pH and PCO2 levels are responded to by the central nervous system's corrective stimulation of the rhythm, effort and rate of breathing. The control and response of the respiratory system takes place within the medulla of the brain stem. The spinal cord serves as the conduit through which the appropriate neural signals are conveyed to the muscles of respiration.
Respiratory drive is affected by the levels of carbon dioxide in the blood. Level changes are detected by central chemoreceptors in the medulla and by peripheral chemoreceptors in the carotid artery and aorta. The feedback loop and resulting neural signals cause breathing patterns to change accordingly and the body is able to maintain the correct acid-to-base and O2-to-CO2 ratios.