Across
- 5. the large sheet of muscle beneath our lungs
- 7. narrow tubes that carry air within the lungs
- 8. the bones around our lungs which act to protect
- 9. two large spongy organs in the breathing system
- 11. tube that carries air into the lungs
- 12. to breathe out
- 13. a gas that makes up 21% of air
Down
- 1. air sacs at the end of bronchioles involved in gaseous exchange
- 2. to breathe in
- 3. commonly known as the windpipe
- 4. tiny blood vessels wrapped around the alveoli
- 6. another name for the respiratory system
- 10. a gas that makes up 78% of air