NEETZoologyBreathing and Exchange of Gases
What is the effect of the contraction of diaphragm on the thoracic chamber?
Options
- AIt decreases the volume of the thoracic chamber
- BIt increases the volume of the thoracic chamber
- CIt has no effect on the volume of the thoracic chamber
- DIt increases the pressure in the thoracic chamber
Correct answer
B. It increases the volume of the thoracic chamber
Step-by-step solution
Breathing involves two stages : inspiration during which atmospheric air is drawn in and expiration by which the alveolar air is released out.The movement of air into and out of the lungs is carried out by creating a pressure gradient between the lungs and the atmosphere. Inspiration can occur if the pressure within the lungs (intra-pulmonary pressure) is less than the atmospheric pressure, i.e., there is a negative pressure in the lungs with respect to atmospheric pressure. Similarly, expiration takes place when t