Across
- 4. the top chambers of the heart
- 5. means something yo do not consciously control
- 8. the type of muscle in the heart
- 9. the system that while blood cells form
- 10. the largest vein
- 12. red blood cells that carry oxygen
- 14. small veins
- 16. protein on red blood cells that alow them to carry oxygen
- 18. vessels which are low in pressure
- 19. vessel which leads to all the body
- 20. the chambers at the bottom of the heart
- 21. structure in the lungs that is surrounded by capillaries
Down
- 1. number of chambers in the human heart
- 2. centre part of the brain that sends pacing signals to the heart
- 3. vessel leading from the lungs to the heart
- 6. keep blood flowing one way
- 7. number of pumps in the body
- 11. lead towards the heart
- 13. white blood cells
- 15. means lungs
- 17. small arteries
- 22. oxygenates the blood