Question

How is respiration regulated?

Answer 1

The respiratory centre present in the medulla of the brain regulates the rate of respiration. It sends signals on change (increase) in carbon dioxide concentration.

Complete Answer:
- The involuntary respiration is controlled by respiratory centres in the upper brain. The respiratory centres contain chemoreceptors that can detect pH levels in blood and send signals to the respiratory centre to adjust pH by increasing or decreasing the carbon dioxide level or hydrogen ion in the blood.
- Hyperventilation causes increase in alkalinity of the blood which causes a response to decreased ventilation i.e. to increase carbon dioxide whereas hypoventilation causes acidosis which causes a response to remove carbon dioxide. Hypoxia or low oxygen level will cause a stimulus to increase ventilation and increase oxygen intake.
- The medulla oblongata is the main centre for respiration. It sends signals which cause breathing. The ventral respiratory region controls expiration movements whereas the dorsal respiratory region stimulates inspiration.
- Pons is another pneumotaxic and apneustic centre. The pneumatic centre directs the respiratory centres for increasing the strength of inspiration.
- The cerebral cortex in the brain controls the voluntary respiration. The phrenic nerves, vagus nerves, and posterior thoracic nerves are involved in respiration.

Additional Information: Medulla oblongata controls all the autonomic function of the brain. It connects the higher level of the brain to the spinal cord for proper functioning of the organs. It is also an important cardiac centre.

Note: Respiration involves inhalation and expiration. Inhalation increases the oxygen level of the blood. Expired air is rich in carbon dioxide. This carbon dioxide signals chemoreceptors which are sensitive to carbon dioxide for inhalation.