Across

1. Where the trachea splits in two, one ... to each lung.
5. Pushing air out of the lungs - breathing out.
8. A thick walled blood vessel that carries blood away from the heart to the rest of the body.
12. Simple sugar fuel used in respiration.
13. Drawing air into the lungs - breathing in.
14. A blood vessel that carries blood back to the heart.
15. Red liquid mixture that carries oxygen and food to every cell.
17. A chemical reaction taking place in all living cells where glucose and oxygen react to release energy.

Down

1. The mechanical movement of air in and out of the lungs.
2. Gas in the atmosphere needed for respiration.
3. Red substance in blood that carries oxygen.
4. The movement of air in and out of the lungs.
6. Muscular organ that pumps blood around the body.
7. A thin blood vessel only one blood cell wide.
9. The windpipe - tube between throat and lungs.
10. Respiration using air is called ...
11. Tiny air bag with large surface area, found in the lungs.
16. Organ in the chest that supplies the body with oxygen