Heart

1. AV valve between the L atrium and ventricle
3. AV valve between the R atrium and ventricle
6. the heart valve in the aorta
8. The intercalated discs in the myocardium contain _______ which are pores in membranes that allow for things to pass between cells. They facilitate the spread of action potentials from cell to cell.
10. are non contractile, self-excitable cells that repeatedly and rhythmically generate and distribute impulses or action potentials through the heart
12. The _____ carry action potentials to the cardiac muscle fibers in the walls of the ventricles stimulating them to contract nearly simultaneously as a single unit.
15. small upward wave (lasting about .08 seconds) caused by atrium depolarization which spreads from the SA node throughout both atria
16. the loose-fitting sac surrounding the heart. Composed of a fibrous outer layer and inner double-layered serous membrane
18. the heart valve in the pulmonary trunk
19. the amount of blood ejected from each ventricle per minute CO=heart rate x stroke volume
20. heart strings; anchors valves to papillary muscles

2. The delay of action potential by the ________ allows the atria to complete contraction before the ventricles contract
4. contraction phase of cardiac muscle
5. the wall or partition which divides the atria into left and right sides
7. the visceral layer of the serous pericardium; outermost layer of the heart wall
9. An ______ is a composite of action potentials generated by cardiac muscle fibers during each heartbeat
11. relaxation phase of cardiac muscle in both atria and ventricle
13. the cavity located between the parietal and visceral layers of the serous pericardium
14. the circulation of deoxygenated blood from the right side of the heart to the lungs
17. the vein that drains most of the heart wall