Across
- 2. established the basic rhythm and rate of the heartbeat (also known as natural pacemaker of the heart).
- 5. any substance that the body regards as foreign.
- 9. the flow of blood only between the heart and lungs
- 11. another term for red blood cells
- 14. the middle and thickest of the heart's three layers.
- 15. abnormal hardening
- 18. another term for leukocytes
Down
- 1. controls the opening between the right atrium and the right ventricle.
- 3. mixture or blending
- 4. fast, rapid
- 6. white
- 7. blood
- 8. smallest veins that join from the larger veins
- 10. arteries
- 12. cells
- 13. small ones
- 16. heart
- 17. vein