THE LUNGS 1 - the rib cage

The ribs
protect the lungs and heart
anchor the intercostal muscles

The intercostal muscles
Contract during inhalation
causing the rib cage to expand ,drawing air into the lungs.
Relax during expiration
causing the ribcage to contract, pushing air out of the lungs

The diaphragm
Is lowered during inspiration and raised during expiration.
Separates the chest area (the thorax) from the lower part of the body (the abdomen).