Concept 3 Review: The Intrinsic Conduction System of the Heart
In the cardiac cycle, the independent contraction and relaxation of heart cells are coordinated through the activity of the heart's intrinsic conduction system and by cell-to-cell communication via the gap junctions in the myocardial cells themselves.
The intrinsic conduction system of the heart consists of nodal tissue, whose specialized cells have both nervous and muscular characteristics. Nodal tissue is localized in specific regions of the heart:





A Closer Look at Cardiac Muscle Cells
The Electrocardiogram