Across
- 2. Main artery leaving the heart
- 4. Organs used for breathing and gas exchange
- 7. Liquid that transports oxygen and nutrients
- 8. Gas needed by cells for respiration
- 11. Blood vessel that carries blood towards the heart
- 13. Organ that pumps blood around the body
- 15. Bones that protect the heart and lung
- 16. The beat you can feel as blood is pumped
- 17. Upper chamber of the heart
- 18. Very small blood vessel where exchange happens
- 19. Smaller branches inside the lungs
- 20. Tube leading from the trachea into a lung
Down
- 1. Waste gas breathed out of the body
- 3. Tiny air sacs where gas exchange occurs
- 5. Structure that prevents blood flowing backwards
- 6. Lower chamber of the heart
- 9. Muscle that helps breathing by moving up and down
- 10. Process by which cells release energy
- 12. Blood vessel that carries blood away from the heart
- 14. Windpipe that carries air to the lungs