Across
- 3. smallest blood vessel
- 5. inner lining of blood vessels
- 6. small artery
- 9. muscle layer of heart
- 13. pacemaker
- 14. small vein
- 15. largest blood vessel
Down
- 1. lower chamber of the heart
- 2. beat of the heart
- 4. tissue dividing the heart into chambers
- 7. graph of heartbeat
- 8. contraction of heart
- 10. relaxation of the heart
- 11. improper closure of valves causes swishing
- 12. largest artery in body