Across
- 2. waste released by body cells
- 5. largest type of blood vessel
- 6. smallest blood vessel
- 8. valve between the right atrium and right ventricle
- 11. membrane surrounding the heart
- 13. small artery
- 15. lower chambers of the heart
Down
- 1. largest artery in the body
- 3. relaxation of the heart
- 4. middle layer of heart muscle
- 7. upper chambers of the heart
- 9. carry oxygen rich blood to heart muscle
- 10. small vein
- 12. innermost lining of blood vessels
- 14. contraction of the heart