What occurs during the process of inhalation?

During inhalation, the diaphragm contracts, which causes it to move downward. This contraction increases the volume of the thoracic cavity, creating a lower pressure within the lungs compared to the outside atmosphere. As a result, air flows into the lungs from the environment. The expansion also involves the intercostal muscles, which assist in lifting the rib cage to further enlarge the thoracic space. This process of creating a negative pressure gradient is essential for drawing air into the lungs, making the contraction of the diaphragm the key action that facilitates inhalation.