ANATOMY OF HEART

1. This connects the umbilical vein to the inferior vena cava in the fetus.
4. Vessel that supplies blood to the heart muscle itself.
7. Node that generates electrical impulses to regulate heart rate.
10. Part of the septum between the ventricles.
11. Inner lining of the heart chambers.
13. Vein that carries blood from the lungs to the heart.
15. The nervous system responsible for modifying the heart rate.
16. Specialized muscle fibers that conduct electrical impulses in the heart.
17. Chamber that receives oxygenated blood from the lungs.
19. They are two of these valves: aortic or pulmonary.
20. Opening between the pulmonary artery and aorta found only in the fetal heart.

2. These are referred to as 'heart strings' and help to keep the AV valve closed.
3. Phase of the heartbeat when the heart muscle contracts.
5. Layer of the heart wall responsible for contractions.
6. Each heartbeat is called this.
8. Main artery that carries blood from the heart to the rest of the body.
9. Valve between the left atrium and left ventricle.
12. Valve between the left ventricle and the aorta.
14. Network of veins that return blood from the heart muscle to the right atrium.
18. Structure preventing backflow into the right atrium.