Stimulation of the phrenic and intercostal nerves cause the respiratory muscles to contract.
During inspiration the contraction of respiratory muscles, diaphragm and the intercostal muscles cause the thoratic cavity to increase in size causing the lungs to expand.
This causes a drop in pressure, lower than in the atmosphere
Air rushes into the lungs
Expiration begins as the elastic recoil of the respiratory muscles causes the lung pressure to increase further.
Comments
No comments have yet been made