Inhalation and Exhalation

• Inhalation

  • The diaphragm contracts and flattens
  • The intercostal muscles contract, lifting the ribs up causing the chest to expand
  • The thoracic cavity increase in size as the chest expands
  • The higher pressure of air outside means air is now sucked into the lungs through the nose and mouth
• Exhalation

  • The diaphragm relaxes, it is pushed upwards
  • The intercostal muscles relax. The ribs move down and inwards and the chest gets smaller
  • The thoracic cavity decrease in size as they are squeezed by the ribs and diaphragm
  • The lower air pressure means we will exhale