Across
- 2. pH-regulating system affected by CO2 levels
- 4. Iron-containing protein in RBC that binds oxygen
- 8. Tiny air sacs where gas exchange occurs
- 11. The act of breathing out
- 13. Primary function of the respiratory system
- 15. Structure that divides into bronchi
- 18. The two branches that lead from the trachea into the lungs
- 20. Fluid lining the alveoli to reduce surface tension
Down
- 1. Brain region that controls breathing rate
- 3. The flap that prevents food from entering the airway
- 5. One-cell thick structures surrounding alveoli
- 6. Process where oxygen and carbon dioxide are exchanges
- 7. Dioxide Gas removed from the body during exhalation
- 9. Gas taken into the body during respiration
- 10. The muscle that contracts during inhalation
- 12. The act of breathing in
- 14. The space between lungs and chest wall
- 16. Main organ of the respiratory system
- 17. The voice box
- 19. Hairs in the nasal cavity that trap particles