Respiratory Control

• The rate of ventilation is controlled by the respiratory control centre in the medulla oblongata
• During exercise, the rate of ventilation changes in response to the amount of CO2 in the blood
• Central chemoreceptors in the medulla oblongata detect changes in CO2 levels (as changes in pH of cerebrospinal fluid)
• Peripheral chemoreceptors in the carotid and aortic bodies detect CO2 levels, as well as O2 levels and blood pH
• During exercise metabolism is increased, leading to a build-up of carbon dioxide and a reduction in the supply of oxygen
• Chemoreceptors detect these changes and send impulses to the respiratory control centre in the brainstem
• Signals are then sent to the diaphragm and intercostal muscles to increase the rate of ventilation (an involuntary process)
• As ventilation rate increases, CO2 levels in the blood drop, restoring blood pH and increasing O2 levels
• Long-term effects of continual exercise may include an improved vital capacity