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Unformatted text preview: autorhythmic cells here, but slower impulses (~50-60/min, called junctional rhythm), so these cells do not set the pace unless there is damage to SA node cells o atrioventricular (AV) bundle (bundle of His) : electrical connection between atria & ventricles; transmits impulse to ventricles o right & left bundle branches : sends impulse along cells of interventricular septum toward apex o Purkinje fibers : extend from inferior aspect of interventricular septum to apex & into outer walls of ventricles- irregular heart rhythms (arrhythmias): o fibrillation : rapid & irregular contractions defibrillation : electrical shock to heart to reset rhythm o ectopic focus: abnormal pacemaker; may be caused by drugs (caffeine, nicotine) or SA node damage o heart block: damage to AV node interferes with impulse transmission to ventricles artificial pacemakers can be used to deliver impulses Page3...
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- Fall '10