Respiratory system

2. Air must move into and out of the lungs so that gasses in the air sacs are continuously refreshed, and this process is commonly called
7. Sometimes referred to as the “guardian of the airways”
8. The lungs occupy the entire thoracic cavity except for the most central area, the mediastinum, which houses the heart, the great blood vessels, bronchi, ..... , and other organs.
9. Oxygen and carbon dioxide must be transported to and from the lungs and tissue cells of the body via the
12. The surface of each lung is covered with a visceral serosa called the
13. the only externally visible part of the respiratory system is the
17. The trachea is lined with ciliated mucosa that beat continuously and in a direction opposite to that of the incoming air as they propel mucus, loaded with dust particles and other debris away from the lungs to the throat, where it can be swallowed or spat out.
18. The pharyngotympanic tubes, which drain the middle ear open into the
19. The narrow, superior portion of each lung,

1. The broad lung area resting on the diaphragm is the
3. The slitlike passageway between the vocal folds is the
4. The nasal cavity is surrounded by a ring of paranasal sinuses located in the frontal, sphenoid, ...... , and maxillary bones
5. During breathing, air enters the nose by passing through the ..... , or nares.
6. The lateral walls of the nasal cavity are uneven owing to three mucosa-covered projections, or lobes called
9. The smallest of the conducting passageways are the
10. The olfactory receptors for the sense of smell are located in the ...... in the slitlike superior part of the nasal cavity
11. The balance of the lung tissue
14. serves as a common passageway for food and air.
15. The terminal bronchioles lead to the respiratory zone structures, even smaller conduits that eventually terminate in ..... or air sacs.
16. The major function of the respiratory system is to supply the body with ..... and to dispose of carbon dioxide.