What is the primary function of the diaphragm during breathing?

The primary function of the diaphragm during breathing is to expand and contract the thoracic cavity. The diaphragm is a dome-shaped muscle located at the base of the thoracic cavity, and its movement directly influences the volume of the chest cavity. When the diaphragm contracts, it flattens, causing the volume of the thoracic cavity to increase. This increase in volume creates a negative pressure that draws air into the lungs. Conversely, when the diaphragm relaxes, it returns to its dome shape, reducing the volume of the thoracic cavity, which forces air out of the lungs. This cycle of contraction and relaxation is essential for the process of respiration, making the diaphragm a crucial muscle for breathing.

Other functions, while important in their contexts, do not primarily relate to the mechanics of breathing. The diaphragm’s unique role in altering thoracic cavity volume is what distinctly defines its function in the respiratory process.