Final answer:
The muscles of inspiration are the diaphragm and the external intercostal muscles. When the diaphragm contracts, it moves downward and expands the thoracic cavity, allowing air to enter the lungs. The external intercostal muscles raise the rib cage, further expanding the thoracic cavity and facilitating inhalation.
Step-by-step explanation:
The muscles of inspiration are the diaphragm and the external intercostal muscles. When the diaphragm contracts, it moves downward and expands the thoracic cavity, allowing air to enter the lungs. The external intercostal muscles raise the rib cage, further expanding the thoracic cavity and facilitating inhalation.
These muscles work together to create a negative pressure within the pleural cavities, which leads to air being drawn into the lungs. Pulmonary ventilation consists of this cycle of inspiration and expiration, where air enters and leaves the lungs respectively.