Across
- 5. small air passages inside the lungs
- 6. a muscle that helps control breathing
- 7. movement of oxygen and carbon dioxide between air and blood
- 10. protein in red blood cells that carries oxygen
- 12. breathing air into the lungs
- 13. the process of breathing and using oxygen to release energy
- 14. organs where oxygen and carbon dioxide are exchanged
Down
- 1. a waste gas removed from the body
- 2. tiny blood vessels surrounding the alveoli
- 3. the windpipe that carries air to the lungs
- 4. breathing air out of the lungs
- 8. tiny air sacs where gas exchange occurs
- 9. two tubes that branch from the trachea into the lungs
- 11. a gas needed by cells to produce energy