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Across 1. What contains incomplete cartilaginous rings and is approximately 11 to 13cm long and lies between the cricoid cartilage and the carina? 8. The movement of gas from a high concentration to a low concentration area. 9. This occurs in the alveolar when oxygen and carbon dioxide transfer across the capillary membrane. 10. The right and left bronchi begin at the _______. 11. Mucus membranes line the respiratory tract and constant movement of mucus by _________ action cleanses the tract and carries foreign matter upward for swallowing or expectoration. 13. The _________ pleura lines the thorax. 14. What coats the alveolus and facilitates gas exchange by lowering surface tension? 17. A valve flap of cartilage that covers the opening to the larynx during swallowing. 19. This impairs ciliary function. 21. The opening between the vocal cords in the larynx 22. What is fully developed by the 8th year of life?

Down 2. Adult lungs contin approximately 300 million of these? 3. The thin alveolar walls contain two basic ______ cell types. 4. The space between the lungs is the _________. 5. The total volume of gas that can be exhaled during maximum expiration. 6. The __________ pleura covers the lungs. 7. The outer surfaces of the lungs are surrounded by this smooth, slippery membrane. 12. The right primary ______ is shorter, widers and more vertical than the left. 15. The volume of gas left in the lungs at the end of a maximum expiration. 16. The thoracic cavity is bounded below by this? 18. This volume is the normal breath or the amount of gas entering or leaving the lung during normal breathing. 20. What cavity conducts gases to and from the lungs and filters, warms and humidifies the air.