In through the nose (nostril) or mouth (oral cavity), a molecule of oxygen comes into the body and makes its way into the respiratory system. The molecule passes over the nasal mucosa, follows the posterior nasal aperture into the nasopharynx, through the oropharynx and finally ending up in the laryngopharynx. The tonsils and adenoids make sure the molecule is moist, warm and filtered. Onto the larynx where it could become a voice sound but we will keep it moving to the trachea. After traveling the 4 inches of hyline cartilage and past the ciliated mucosa it enters the main bronci. In the lungs, the oxygen molecule is pushed into the secondary andtertiary bronchi until it ends in the bronchioles and alveoli. The alveoli are where the oxygen
