2.45 understand the role of the intercostal muscles and the diaphragm in ventilation

Intercostal muscles:

Inspiration:

·         The external intercostal muscles contract

·         Causes the rib cage to be lifted up and out

·         This increases the thoracic volume and causes air to rush in filling the space

Expiration:

·         The internal intercostal muscles contract

·         Causes the ribs the be pulled down and in

·         This reduces the thoracic volume causing air to rush out