Inhalation is the process of taking air into the lungs. It occurs when the diaphragm, a muscle located beneath the lungs, contracts and moves downward. This action creates a vacuum that pulls air through the nose or mouth and into the trachea, leading to the lungs. During inhalation, oxygen from the air enters the bloodstream through tiny air sacs called alveoli. This oxygen is essential for the body's cells to produce energy. Inhalation is a vital part of the respiratory cycle, which also includes exhalation, the process of releasing air from the lungs.