Question

Explain the mechanism of breathing.

Answer 1

Breathing:

1. Breathing is the process of moving air to and fro from the lungs and conducting gas exchange.
2. It involves two stages - Inspiration and Expiration. During inspiration, atmospheric air is drawn into the lungs while air is expelled out during expiration.
3. Breathing occurs when the muscles around the lungs contract or relax altering the volume of the lung. If the pressure is greater in the lungs, air rushes out while air rushes in if the pressure inside the lungs is lower.
4. Inspiration occurs when the diaphragm and intercostal muscles contract and increase the size of the thoracic cavity. The volume of the internal air passage increases and gas moves in from region of high pressure to low pressure.
5. Expiration occurs when the diaphragm and external intercostal muscles relax. The elastic fibers of the lung tissues recoil and return the lung to its original volume.
6. The pressure inside the lungs increases and is high compared to the air pressure outside the body, and thus air rushes out.
7. Expiration occurs by the contraction of the expiratory muscles.