- Inhalation or Inspiration
It is the taking in of air into the lungs during inspiration, the external inter coastal muscle of the thoracic cavity contract and the ribs move upward and downward.
- The diapharm is flattern due to contraction of muscles hence making the lungs to expand and the ribcage assume a dome shape structure.
- The volume of the lungs increases as the pressure drops. The internal intercoastal muscle relax and that result in the increase of the volume of the thoracic cavity.(diagram of inspiration)
- Expiration
It is the sending out of expired air or carbondioxide from the lung. During Breathing out of expiration or oxohalation the external intercoastal muscle relaxes and the internal intercoastal muscle contract and this causes the ribcage to move downward and inward and the diaphragm muscle relaxes assuming it is a dome shape. This result a decrease in the volume of the thoracic cavity and an increase in the pressure around the lungs which rises above the external air pressure around the lungs which rises above the external air pressure and therefore air rushes out of the lungs.
