Across
- 6. Found in insects and some arthropods, air enters through openings called ___ and moves to cells directly through tracheae
- 8. The volume of the thoracic cavity is decreased by the upward movement of the diaphragm
- 9. How many small aquatic animals perform gas exchange
- 13. Branches into two bronchi, which connects to the lungs
- 15. In bony fishes, a ___ exchange system increases the efficiency of gills
- 16. Where gas exchange takes place at the end of each bronchiole
- 17. How carbon dioxide is transported in body
- 18. ___ flow is air being breathed in and out
- 20. The bronchi branch into small ___
- 21. These organisms have the most efficient respiratory systems
Down
- 1. Closes the larynx when food is swallowed
- 2. A respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide
- 3. Conducts air to the larynx
- 4. The exchange of gases between and organism and its environment
- 5. Breathing is an involuntary process regulated by respiratory centers in the ___ (two words)
- 7. Inversely proportional to volume
- 10. The volume of the thoracic cavity is increased by the downward movement of the diaphragm
- 11. The circulatory system carries ___ from alveoli to body cells
- 12. Sensitive to changes in pH and stimulate respiratory centers
- 14. ___ cavities filter and adjust temperature and humidity in air
- 19. Where air enters in mammals