What occurs during inhalation?

During inhalation, the diaphragm and intercostal muscles contract. This contraction causes the diaphragm to move downward and the rib cage to expand outward, which in turn increases the volume of the thoracic cavity. As the volume of the thoracic cavity increases, the pressure inside the cavity—known as intrathoracic pressure—decreases relative to the atmospheric pressure outside the body. This pressure difference allows air to flow into the lungs from the environment, facilitating the process of breathing.

The mechanics of inhalation are crucial for understanding respiratory physiology in a medical context, as they demonstrate how the body effectively draws in oxygen-rich air to support vital functions. Without the contraction of these muscles, the necessary changes in pressure to allow air influx would not occur.