Question

Select the correct events that occur during expiration.
a. Contraction of diaphragm
b. Pulmonary volume decreases as diaphragm becomes dome shaped
c. Increase in intra pulmonary pressure
d. Contraction of external inter-costal muscles

• A. a and b
• B. b and c
• C. c and d
• D. a and d

Answer 1

The correct option is B b and c

Contraction of diaphragm and external intercostal muscles occur during inspiration. These muscles relax during expiration which leads to decrease in volume of lungs and thus increase in intra pulmonary pressure.