Respiratory System

3. the air tube that extends from the larynx into the thorax, where it splits into the right and left bronchi; the windpipe
5. the structure consisting of hard and soft components that separates the oral and nasal cavities; the roof of the mouth
6. the two openings in the nose through which air enters; nostrils
8. air sacs in the lungs from which gas is exchanged with the capillaries
9. the thin-walled branches of the bronchi; the smallest air- conducting passageways of the bronchi
10. a phospholipid that reduces the surface tension in the alveoli and prevents them from collapsing
12. the area of the thoracic cavity between the lungs; houses the heart, great blood vessels, trachea, esophagus, thoracic duct, thymus gland, and other structures
13. a flap of cartilaginous tissue that covers the opening to the trachea; diverts food and liquids to the esophagus during swallowing
15. the air-filled cavities that surround the nose

1. the collective name for the respiratory and cardiovascular systems; these systems work together to conduct gas exchange
2. the thin, double-walled serous membrane that surrounds the lungs
4. three uneven, scroll-like nasal bones that extend down through the nasal cavity
5. the two passageways that branch off the trachea and lead to the right and left lungs
7. the muscular passageway that extends from the nasal cavity to the mouth and connects to the esophagus; the throat
11. clusters of lymphatic tissue in the pharynx that function as the first line of defense against infection
14. triangular -shaped space inferior to the pharynx that is responsible for voice production; the voice box