Heart Terminology

4. The oxygen carrying protein found in muscle
5. Attachments on the heart valves that prevent the valves from inverting, but do not open/close them
7. Area of medulla oblongata that can speed up or slow down the heartbeat
8. Liquid within the pericardial sac that prevents friction on the heart as it beats
9. Forms when the foramen ovalus closes before a fetus is born
12. Fully innervates the whole ventricles so they contract as a unit
15. Pacemaker cell that initiate the heartbeat
16. The electrical system of the heart that keeps its own pace and spreads action potentials to the whole heart

1. Thickest layer of the heart wall
2. The vessel that drains deoxygenated blood used by the heart back to the right atrium
3. Runs down the interventricular septum and branches to the left and right
6. Visceral layer of serous pericardium
10. Bundle of cells where electrical impulses pause
11. The protective covering that sits on top of the heart
13. The innermost layer of heart wall, continuous with blood vessels/smooth surface for RBCs to flow over
14. The connections between cardiac muscle made up of desmosomes and gap junctions