1334
227
Breathing and Exchange of Gases
Report Error
Solution:
• Inspiration is initiated by the contraction of diaphragm which increases the volume of thoracic chamber in the anterior-posterior axis.
• During inspiration diaphragm contract and become flat.
• The contraction of external inter-coast al muscles lifts up the ribs and the sternum causing an increase in the volume of the thoracic chamber in the dorsoventral axis. The overall increase in the thoracic volume
causes a similar increase in pulmonary volume
• An increase in pulmonary volume decreases the intrapulmonary pressure to less than the atmospheric pressure which forces the air from outside to move into the lungs, i.e. inspiration.