Understanding:
• 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
The respiratory control centre in the medulla oblongata responds to stimuli from chemoreceptors in order to control ventilation
- 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 also detect CO2 levels, as well as O2 levels and blood pH
During exercise metabolism is increased, which results in a build up of carbon dioxide and a reduction in the supply of oxygen
- These changes are detected by chemoreceptors and impulses are sent to the respiratory control centre in the brainstem
- Signals are sent to the diaphragm and intercostal muscles to increase the rate of ventilation (this process is involuntary)
- As the ventilation rate increases, CO2 levels in the blood will drop, restoring blood pH (also O2 levels will rise)
- Long term effects of continual exercise may include an improved vital capacity
Respiratory Control
