Q. Decreased intrapulmonary pressure during inspiration is caused due to

 135  159 Breathing and Exchange of Gases Report Error

Solution:

Option (d) is correct and can be explained as Inspiration is initiated by the contraction of diaphragm. It is achieved by the contraction of the external intercostal muscles which up lift the ribs and the sternum. The overall increase in the thoracic volume causes a similar increase in the pulmonary volume. This decreases the intrapulmonary pressure forcing the air from outside to move into the lungs (i.e. inspiration).