What occurs during exhalation in the respiratory process?

During exhalation, the diaphragm relaxes and moves upward into the thoracic cavity, which decreases the volume of the thoracic cavity. This reduction in volume creates an increase in pressure within the lungs compared to the atmospheric pressure, causing air to flow out of the lungs. This process is often passive, primarily driven by the natural elasticity of the lung tissue and the thoracic cavity.

The role of the diaphragm during exhalation is crucial. When the diaphragm relaxes, it no longer actively contracts as it does during inhalation, leading to the expulsion of air from the lungs. The movement of the diaphragm is a key factor that differentiates inhalation—where it contracts and moves downward to increase lung volume—from exhalation, where it relaxes and causes air to exit the lungs.

This understanding is essential in the context of how the respiratory system operates. Knowing the mechanics of breathing aids in comprehending various respiratory functions and the physiological responses of the body during different states, such as rest or exercise.