Crossword

4. / the movement of an artery as it stretches and relaxes with the flow of blood from the heart.
7. / top chamber of the heart into which blood enters.
8. / impulses cause the muscle of the heart to contract.
9. / inner lining of the heart.
13. / blood vessel that carries oxygenated blood to the body.
15. / tiniest of the blood vessels.
16. / blood vessel that brings blood back to the heart from parts of the body.
17. valve / valve between the right atrium and right ventricle.
18. veins / veins that carry blood from the lungs back to the heart.

1. / flap of tissue that covers the atrium.
2. / strongest muscle in the body.
3. / muscular partition that divides the heart into a left pump and a right pump.
5. valve / valve between the left atrium and left ventricle.
6. / sheet-like muscle located below the heart.
10. / muscular layer of the heart.
11. / spaces inside the heart.
12. / artery that carries blood from the heart to all other arteries.
14. / small, round structures in the blood that help the blood to clot.
15. / to reduce in size by squeezing or drawing together.
18. / liquid part of the blood.