respiratory system


respiratory system

/

As air enters the nasal cavity through the nostrils, it is warmed and moistened by mucous membranes …—© Merriam-Webster Inc.

Organ system involved in respiration. In humans, the diaphragm and, to a lesser extent, the muscles between the ribs generate a pumping action, moving air in and out of the lungs through a system of pipes (conducting airways), divided into upper and lower airway systems. The upper airway system comprises the nasal cavity (see nose), sinuses, and pharynx; the lower airway system consists of the larynx, trachea, bronchi, bronchioles, and alveolar ducts (see pulmonary alveolus). The blood and cardiovascular system can be considered elements of a working respiratory system. See also thoracic cavity.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on respiratory system, visit Britannica.com.

Seen & Heard

What made you look up respiratory system? Please tell us what you were reading, watching or discussing that led you here.