Electrical indicators arising inside the SA node (located in the right atrium) stimulate the atria to agreement. Then the indicators travel to the atrioventricular node (AV node), which is located in the interatrial septum. After a put off, the electric signal diverges and is conducted thru the left and right bundle of His to the respective Purkinje fibers for every side of the heart, in addition to to the endocardium at the apex of the coronary heart, then in the end to the ventricular epicardium; causing its contraction. These indicators are generated rhythmically, which in turn results in the coordinated rhythmic contraction and relaxation of the heart.
On the microscopic stage, the wave of depolarization propagates to adjacent cells via gap junctions positioned at the intercalated disc. The coronary heart is a practical syncytium (no longer to be stressed with a real “syncytium” in which all of the cells are fused together, sharing the identical plasma membrane as in skeletal muscle). In a practical syncytium, electric impulses propagate freely between cells in each direction, so that the myocardium functions as a single contractile unit. This belongings permits rapid, synchronous depolarization of the myocardium. While superb under regular instances, this belongings may be detrimental, because it has capability to allow the propagation of incorrect electric indicators. These gap junctions can close to isolate damaged or demise tissue, as in a myocardial infarction (coronary heart assault).