Explain the mechanism of breathing with neat labelled sketches.
Answers (1)
The process of breathing comprises of two stages: - Inspiration:
The intercostal muscles initiate contraction of the diaphragm. This increases the volume of the thoracic chamber.
Ribs and diaphragm are moved upwards. As a result, the pressure inside the lungs becomes less than atmospheric pressure. This difference in pressure causes air to move inside the lungs.
Expiration:
The intercostal muscles and the diaphragm relax and move to their original position.
Ribs and sternum return to their original position.
The volume inside the thoracic chamber reduces. As a result, the pressure inside the lungs becomes more than the atmospheric pressure and the air is forced out of the lungs.