As the thoracic muscles relax, what happens to the volume of the thoracic cavity?
1 Answer
Nov 13, 2016
Comes to its normal position
Explanation:
As the thoracic muscles relax thoracic volume comes to its normal position.
During inspiration
- Diaphragm contracts leading to increase in volume of thoracic chamber in the antero-posterior axis
- Contraction of external inter-costal muscles lifts up the ribs and sternum causing an increase in the volume of the thoracic chamber in the dorso-ventral axis
- Hence there is an increase in pulmonary volume
During expiration
- Relaxation of Diaphragm and external inter-costal muscles returns the diaphragm and sternum to their normal positions and reduces the pulmonary volume.
