Across
- 6. mucus
- 7. innermost lining of the blood vessels
- 8. largest type of blood vessel
- 9. muscular middle layer of the heart
- 10. smallest type of blood vessel
- 12. pacemaker of the heart
- 13. pericarium
- 14. small vein
Down
- 1. small artery
- 2. relaxation phase of the heartbeat
- 3. lower chambers of the heart
- 4. contraction phase of the heartbeat
- 5. partition or wall dividing a cavity
- 9. valve between the left atrium and the left ventricle
- 11. yellowish plaque, fatty substance