What occurs during the process of inspiration?

During the process of inspiration, the chest cavity expands, which leads to a decrease in air pressure within the lungs. This pressure differential causes air to flow in from the outside environment. The diaphragm, a dome-shaped muscle at the base of the lungs, contracts and moves downward, while the intercostal muscles between the ribs also contract, lifting the rib cage upwards and outwards. Together, these actions increase the volume of the thoracic cavity, subsequently reducing the internal lung pressure below atmospheric pressure. As a result, air is drawn into the lungs through the respiratory passages.

This understanding of the mechanics of inspiration is crucial for those studying physical therapy and respiratory physiology, as it highlights the importance of muscle function and pressure changes in pulmonary ventilation.