Anatomy Chapter 20

2. A period of contraction in a chamber of the heart, as part of the cardiac cycle.
3. An abnormally slow heart rate, usually below 50 bpm
6. The coronary sinus drains___blood from the heart into the right atrium.
7. Part of the coronary circulation becomes blocked, and cardiac muscle cells die from lack of oxygen.
9. Is called the natural pacemaker of the heart, generates action potentials, and sets the heart rate at about 70-80 bpm.
11. Receives blood from the pulmonary circuit and empties it into the left ventricle.
13. Repolarization of the ventricle.
14. ____cells produce powerful contractions that propel blood.
19. ___cells of the SA node that set the pace of cardiac contraction.
20. An irregular rhythm or force of the heartbeat.
21. A blood clot that blocks blood flow.
22. A period of relaxation in a chamber which fills with blood and prepares for the next cardiac cycle.

1. Pathogens can infect the pericardium, producing inflammation.
4. When the ventricles contract with all 4 valves closed.
5. Marks the beginning of the ventricular depolarization.
8. Is located on the floor of the right atrium near the opening of the coronoary sinus.
10. Return blood into the heart.
12. Carry blood away from the heart.
15. How much blood was pushed out is known as____.
16. Receives blood from the systemic circuit and passes it on to the right ventricle.
17. Rapid heart beat usually over 90 bpm
18. Depolarization of the atria.