What is the primary function of the diaphragm in respiration?

The primary function of the diaphragm in respiration is to create negative pressure for inhalation. During the process of breathing in, or inhalation, the diaphragm contracts and moves downward. This movement increases the volume of the thoracic cavity, which in turn lowers the pressure inside the lungs compared to atmospheric pressure. As a result, air flows into the lungs to equalize the pressure difference, enabling effective inhalation.

While the diaphragm plays a role in ventilation that ultimately supports gas exchange, its main function is facilitating the airflow into the lungs through the creation of negative pressure. This anatomical and physiological dynamic is crucial for proper respiratory function.