What physiological change occurs when the diaphragm contracts?

When the diaphragm contracts, it moves downward into the thoracic cavity, leading to an increase in thoracic volume. This physiological change allows for more space within the chest cavity, which reduces the pressure inside the lungs relative to the outside atmosphere. As a result, air flows into the lungs due to this pressure difference, facilitating inspiration.

The increase in thoracic volume is crucial for effective breathing, as it creates a vacuum that draws air into the lungs. This process is fundamental for gas exchange, as it allows oxygen to enter the bloodstream and carbon dioxide to be expelled from the body during exhalation. Understanding this mechanism is essential for grasping how the respiratory system functions during the breathing cycle.