Across
- 2. White cells ingesting bacteria.
- 4. White cells producing antibodies.
- 8. Membrane lining the heart's interior.
- 10. Major artery carrying oxygenated blood.
- 11. Vessels carrying blood to heart.
- 12. Vessels carrying blood away from heart.
- 14. Main organ of the circulatory system.
- 15. Structures controlling blood flow direction.
- 17. White blood cells fighting infection.
- 18. Lower heart chambers.
Down
- 1. Red blood cells transporting oxygen.
- 3. Platelets aiding blood clotting.
- 5. Relating to lungs and blood flow.
- 6. Tiny blood vessels for substance exchange.
- 7. Liquid component of blood.
- 9. SA node controlling heart rate.
- 13. Phase of heart contraction.
- 14. Protein in red cells binding oxygen.
- 16. Upper heart chambers.
- 19. Muscular wall dividing heart halves.