question_answer 6)

Explain the process of inspiration under normal conditions. 

Answer:

Inspiration   is   the process during which atmospheric air is drawn in. Inspiration is initiated by the contraction of diaphragm, which increases the volume of thoracic chamber in the antero-posterior axis. The contraction of external intercostal muscles lifts up the ribs and the sternum causing an increase in the volume of the thoracic   chamber   in   the dorso-ventral 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. On an average, a healthy human breathes 12-16 times/minute.