An interconnected series of air passages, cavernous organs, and cells that permit the introduction of oxygen, the exchange of gases, and the removal of carbon dioxide from the body as well as, in humans, the production of seech.

The anatomical components involved include the external nose and nasal cavity, the oral cavity and pharynx, paranasal sinuses, larynx, trachea, bronchi, lungs, and thoracic cavity; as well as, the muscles related to their activities or functions.