Inhalation is the process that allows air to enter the body while exhalation allows air out of the body. During inhalation, the diaphragm and the rib muscles contract, increasing the volume of the lungs. Air enters the nose or the mouth and flows down the trachea, bronchi, and bronchioles and into the alveoli. On the other hand, during exhalation, the diaphragm and the rib muscles relax, decreasing the volume of the thoracic cavity, Air leaves the alveoli and flows up the bronchioles, bronchi, and trachea and exits through the nose or the mouth.
