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Stack #23792
Electrical Conducting System
electrical conducting system | Answer |
---|---|
SA node | patch of modified myocytes (muscle cells), in the R atrium just under epicardium near superior vena cava. This is heart's PACEMAKER that initiates each heartbeat and determines heart rate. Depolarizes at 70-80 bpm. Known as SINUS rhythm. |
AV node | located near R AV valve at lower end of interatrial septum. Acts as electrical gateway to ventricles. Depolarizes at 40-50 bpm. Known as NODAL rhythm. |
AV bundle (bundle of His) | pathway by which signals leave AV node. 20-30 bpm on its own |
R and L bundle branches | divisions of bundle of His that enter interventricular septum and descend toward apex |
Purkinje fibers | nerve-like processes that arise from bundle branches near apex of heart, and then turn upward and spread through ventricular myocardium |