Across
- 4. relaxation phase of the heartbeat
- 8. specialized nervous tissue in the right atrium that begins the heartbeat
- 9. small artery
- 12. double layered membrane surround the heart
- 13. small vein
- 15. gas that enters the blood through the lungs
Down
- 1. muscular middle layer of the heart
- 2. abnormal swishing sound caused by improper closure of the heart valves
- 3. smallest type of blood vessel
- 5. larger artery in the body
- 6. beat of the heart as felt through the walls of the artery
- 7. innermost lining of blood vessels
- 10. inner lining of the heart
- 11. larger type of blood vessel
- 14. record of the electrical activities of the heart