Inhalation and exhalation are the two phases of breathing or respiration. During inhalation, also known as inspiration, the diaphragm contracts and pulls downward, while the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside, allowing air to rush in and fill the lungs with oxygen. On the other hand, during exhalation, also known as expiration, the diaphragm relaxes, and the volume of the thoracic cavity decreases, while the pressure within it increases. As a result, the lungs contract, and air is forced out, containing carbon dioxide. The following are the differences between inhalation and exhalation:

• Inhalation:

  • The process of inhaling air containing oxygen.
  • During this process, the size of the chest cavity will be increased.
  • As the chest cavity increases, the air pressure inside will be less.
  • Air from outside runs into the lungs.
  • The diaphragm contracts and flattens.

• Exhalation:

  • The process of exhaling air containing carbon dioxide.
  • During this process, the size of the chest cavity will be decreased.
  • As the chest cavity decreases, the air pressure inside will be more.
  • Air moves out from the lungs.
  • The diaphragm relaxes and becomes dome-shaped.

Understanding how inhalation and exhalation work is essential to understanding how the lungs function and how to keep them healthy.