What is the role of the diaphragm during breathing?

The diaphragm plays a crucial role in the breathing process primarily by creating negative pressure in the thoracic cavity. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity. This expansion lowers the pressure within the thoracic cavity compared to the atmospheric pressure outside of the body. As a result, air is drawn into the lungs, a process known as inhalation.

This function is central to the mechanics of breathing and enables efficient gas exchange in the lungs. During exhalation, the diaphragm relaxes, reducing the volume of the thoracic cavity and increasing the pressure, which forces air out of the lungs. Thus, the diaphragm's ability to create negative pressure is essential for the inhalation aspect of respiration.