What enables us to breathe?

The diaphragm:

- The dome-shaped muscle separates the lungs from the digestive organs.

- Contraction of the diaphragm increases the chest cavity volume, expanding the lungs so that air rushes in during inhalation. Diaphragm relaxation allows exhalation to occur passively as air flows out of the lungs.

-Innervated by the phrenic nerve; blood supply from musculopragmatic, superior diaphragmatic and pericardiophrenic arteries. It receives lymphatic supply of internal and external thoracic nodes and anterior mediastinal nodes.