BIOL 208 Study Guide - Midterm Guide: Tachycardia, Aortic Valve, Heart Murmur
31 Oct 2017
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Anatomy and physiology ii exam ii special assignments. Defects in intrinsic conduction system can cause arrhythmias, uncoordinated atrial and ventricular. Fibrillating ventricles are useless, and unless heart defibrillated quickly circulation stops brain death. Defibrillation accomplished by electrically shocking heart, interrupts chaotic twitching by depolarizing entire myocardium, hope sa node begin function normally and sinus rhythm reestablished. Implantable cardioverter defibrillators (icds) can monitor and slow abnormally fast heart rate or emit electrical shock if heart begins to fibrillate. Defective sa node several consequences: ectopic focus may appear, or av node may become pacemaker. Pace set by av node (junctional rhythm) is 40-60 bpm, slower than sinus rhythm but adequate maintain circulation. Only route for impulse transmission from atria to ventricles is through av node, av bundle, bundle branches, damage to any structures may cause heart block. Total heart block- no impulses get through and ventricles beat at their intrinsic rate, too slow to maintain adequate circulation.
