What term describes the filling of the lungs with air?

The term that describes the filling of the lungs with air is inspiration. During inspiration, the diaphragm and intercostal muscles contract, increasing the volume of the thoracic cavity. This creates a negative pressure in the lungs compared to the outside atmosphere, causing air to flow into the lungs. It is a crucial part of the ventilatory process, which involves the movement of air in and out of the lungs. Understanding this mechanism is essential in studying how organisms obtain oxygen for metabolic processes.

Other terms like expiration refer specifically to the process of exhaling air from the lungs, while ventilation generally encompasses both inspiration and expiration as the complete movement of air in and out of the respiratory system. Respiration, on the other hand, refers to the biochemical processes that occur in cells, where oxygen is used to produce energy, and carbon dioxide is produced as a waste product.