During inhalation, what happens to the pressure within the thorax?

During inhalation, the diaphragm and intercostal muscles contract, which leads to an expansion of the thoracic cavity. This expansion decreases the pressure within the thorax compared to atmospheric pressure. Because the pressure inside the thorax is now lower than the air pressure outside the body, air flows into the lungs to equalize the pressure difference. This process is crucial for the mechanics of breathing, as it allows oxygen-rich air to enter the lungs, which is essential for gas exchange.

The mechanics of this process highlight importance of pressure changes in the thoracic cavity during inhalation, demonstrating the critical role of the diaphragm and the thoracic muscles in creating a pressure gradient that facilitates breathing.