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Unformatted text preview: and relaxation occurs and prevents tetany in cardiac muscle. o The SA node located in the upper wall of the right atrium is the normal pacemaker of the heart and cells of the SA node have more voltage-gated calcium ion channels than other areas of the heart. Conduction System of the Heart o The conduction system of the heart is made up of specialized cardiac muscle cells. o The SA node produces action potentials that are propagated over the atria to the AV node. o The AV node and atrioventricular bundle conduct action potentials to the ventricles. o The right and left bundle branches conduct action potentials from the atrioventricular bundle through Purkinje fibers to the ventricular muscle. o An ectopic beat results from an action potential that originates in an area of the heart other than the SA node....
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- Fall '10