Final answer:
Inhalation is the active process of the diaphragm contracting and the chest expanding, which reduces intrapleural pressure and allows air to enter the lungs. Exhalation is a more passive process where the diaphragm and chest relax, pushing air out due to the natural elasticity of the lungs and increased thoracic pressure.
Step-by-step explanation:
When you inhale, your chest moves upward and outward as it expands, allowing air to move into your body. This occurs because the diaphragm contracts and the chest wall expands outward. The intrapleural pressure drops, and air is drawn into the airways.
As the lungs expand, the elastic tissues within create an opposing force that aids in deflation during exhalation. During exhalation, the diaphragm relaxes, the chest contracts as the intercostal muscles relax, and air flows out in a passive process due to the elasticity of the lungs and the increased pressure within the thoracic cavity.