Across
- 5. contraction phase of the heart
- 7. record of electrical activity of the heart
- 10. one of two upper chambers of the heart
- 11. smallest type of blood vessel
- 12. gas, waste
- 13. relaxation phase of heartbeat
- 14. the largest artery in the body
- 15. artery carrying oxygen-poor blood from the heart to the lungs
- 18. double layered membrane surrounding the heart
Down
- 1. gas that enters the blood through the lungs
- 2. largest vein in the body
- 3. the center of a humans circulatory system
- 4. valve between the left atrium and left ventricle
- 6. pacemaker of the heart
- 8. abnormal swishing sound
- 9. carries blood away from the heart
- 16. inner lining of the heart
- 17. beat of the heart