What is the prime mover of respiration that accounts for the majority of air flow?

The diaphragm is the primary muscle responsible for the majority of airflow during respiration. It is a dome-shaped muscle located beneath the lungs that separates the thoracic cavity from the abdominal cavity. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity and creating a negative pressure which draws air into the lungs. This action is essential for inhalation.

The diaphragm's role is particularly crucial because it accounts for approximately 75% of the airflow during quiet breathing. During active breathing, such as during exercise, the intercostal muscles may assist by elevating the rib cage, but the diaphragm remains the main driver of inhalation. Understanding the diaphragm's function highlights its significance in the respiratory process, as it is the essential component that initiates and facilitates breathing effectively.