2. Your heart is a muscle that works continuously like a pump Each beat of your heart is set in motion by an electrical signal from within your heart muscle The electrical activity can be recorded by an electrocardiogram (aka EKG or ECG)

3. Each beat of your heart begins with an electrical impulse from the sinoatrial node in the right atrium – A cluster of cells where electrical impulses are generated When you heart’s right atrium is full with blood, the electrical signal spreads across the cells of your heart’s right atria. Signal causes atria to contract or squeeze, forcing blood into the ventricles. The SA node sets the rate and rhythm of your heartbeat. – Known as the heart’s natural pacemaker.

5. The signal arrives at the atrioventricular (AV) node between the atria and the ventricles. Here the impulse slows for an instant to allow your heart’s right AND left ventricles to fill with blood – Pumps the breaks!

7. The signal is released and moves to the bundle of His located in the heart’s ventricles. The signal fibers divided into left and right branches which run through the heart’s septum

9. The signal leaves the left and right branches through the Purkinje fibers that connect directly to the walls of the heart’s ventricles The signal spreads quickly across your heart’s ventricles

11. As the signal spreads, both ventricles contract, but not at exactly the same moment… – The left ventricles contracts an instant before the right. Right ventricle pushes blood to the lungs Left ventricle pushes blood to the rest of the body

12. As the signal passes, the walls of the ventricles relax and await the next signal.

17. How fast the heart beats depends on the body's need for oxygen-rich blood. At rest, the SA node causes your heart to beat about 50 to 100 times each minute. During activity or excitement, your body needs more oxygen-rich blood; the heart rate rises to well over 100 beats per minute.

18. The heart’s electrical system triggers the heartbeat. Each beat of the heart is represented on the electrocardiogram (EKG or ECG) by a wave arm. The normal heart rhythm (normal sinus rhythm) shows the electrical activity in the heart is following the normal pathway. The rhythm is regular and the node is normal (about 50 to 100 beats per minute).

19. Tachycardia: fast heart rhythm (greater than 100 beats per minute) Bradycardia: slow heart rhythm (less than 50 beats per minute)

21. An arrhythmia (also called dysrhythmia) is an irregular or abnormal heartbeat.

22. Coronary artery disease High blood pressure Changes in the heart muscle (cardiomyopathy) Valve disorders Electrolyte imbalances in the blood, such as sodium or potassium Injury from a heart attack The healing process after heart surgery Other medical conditions

23. Palpitations: A feeling of skipped heartbeats, fluttering, "flip-flops" or feeling that the heart is "running away" Pounding in the chest Dizziness or feeling lightheaded Shortness of breath Chest discomfort Weakness or fatigue

24. http://www.pbs.org/wnet/heart/educators/vi deo-spark.html http://www.pbs.org/wnet/heart/educators/vi deo-spark.html http://www.pbs.org/wnet/heart/educators/vi deo2-spark.html http://www.pbs.org/wnet/heart/educators/vi deo2-spark.html As you watch take note of the questions that accompany each clip and jot down your observations.

25. Atrial Fibrillation Atrial Flutter Supraventricular Tachycardia Sick Sinus Syndrome Ventricular Fibrillation Ventricular Tachycardia Premature Contractions Heart Block You will each select one type of Heart Arrhythmia Disorders You will conduct research and create a presentation on one of the disorders: – Describe the disorder – What are the signs and symptoms – What are the causes? – What remedies are there for treating the disorder?