Across
- 4. bones around each lung that protect it
- 7. blood vessels in the walls of alveoli
- 8. what you use to breath
- 9. air sacs that exchange oxygen and carbon dioxide in the blood
- 11. what you breath in
- 13. inflates and deflates the lungs
Down
- 1. small air tubes that connect the bronchus to the alveoli
- 2. found at the end of the trachea and splits into each lung
- 3. air sacs that exchange oxygen and carbon dioxide
- 5. waste your body doesn't need
- 6. movement of a substance from an area of high concentration to an area of lower concentration
- 10. the organ that collects air
- 12. pipe that sends air to the lungs