NEET2009ZoologyBreathing and Exchange of GasesActual
During inspiration, the diaphragm
Options
- Aexpands
- Bshows no change
- Ccontracts and flattens
- Drelaxes to become dome-shaped
Correct answer
C. contracts and flattens
Step-by-step solution
During inspiration, the diaphragm contracts and flattens to increase the volume of the the thoracic cavity. This increase in volume leads to a decrease in intra-alveolar pressure, which is a pressure lower than atmospheric pressure and creates the pressure gradient. Due to the gradient the air is from the atmosphere is forced inside the lungs through nasal cavity. So, the correct answer is 'Contracts and flattens'.