Diaphragm, Rib Cage & Lungs: What Happens During Exhalation?

When you exhale, the following changes occur:

1. Diaphragm: The diaphragm, a dome-shaped muscle located at the base of the chest, contracts and moves upward. This action decreases the volume of the thoracic cavity.

2. Rib Cage: The rib cage, which encloses the chest cavity, slightly lowers and narrows as the ribs move downward and inward. This movement further reduces the volume of the thoracic cavity.

3. Lungs: As the diaphragm contracts and the rib cage moves downward, the volume of the thoracic cavity decreases. This decrease in volume creates a negative pressure inside the pleural space, the area between the lungs and the chest wall. As a result, the lungs passively recoil and collapse, expelling air from the respiratory system.

The coordinated actions of the diaphragm, rib cage, and lungs lead to the expulsion of air from the body during exhalation.