Breathing and Exchange of Gases Question 2
2. Select the correct statement. [2019, Odisha]
(a) Expiration is initiated due to contraction of diaphragm.
(b) Expiration occurs due to external intercostal muscles.
(c) Intrapulmonary pressure is lower than the atmospheric pressure during inspiration.
(d) Inspiration occurs when atmospheric pressure is less than intrapulmonary pressure.
Show Answer
Answer : c
Hints & Solution
(c) During inspiration, diaphragm and external intercostal muscles contract causing increase in volume of thoracic cage. As a result intrapulmonary pressure decreases to a level less than atmospheric pressure, thus causing inspiration. Expiration is initiated due to relaxation of diaphragm.
