NEET2020ZoologyBreathing and Exchange of GasesActual
Select the correct events that occur during inspiration. (a) Contraction of diaphragm (b) Contraction of external intercostal muscles (c) Pulmonary volume decreases (d) Intrapulmonary pressure increases
Options
- A(c) and (d)
- B(a), (b) and (d)
- Conly (d)
- D(a) and (b)
Correct answer
D. (a) and (b)
Step-by-step solution
INSPIRATION: Inspiration is an active process involving the contraction of the muscles. The external intercostal muscles contract, making the ribs move outward, sideward and upward. This increases thoracic volume. Simultaneously the muscles of the diaphragm also contract and the diaphragm becomes a flattened sheet, further increasing the thoracic volume. This decreases intrapleural pressure and the pressure in the lungs. This decrease in the pressure makes the air rush in from the surrounding atmosphere into the lu