Structure of the Conduction System of the Heart
Sinoatrial (SA) Node is the pacemaker node located in the right atrium near the opening of superior venacava. It is called the "pacemaker" of the heart. Inter-nodal tracts connect SA and AV nodes.
Atrio-ventricular (AV) node located on the right side of inter-atrial septum.
Bundle of His: Thick cable of fibers starting at the AV node, bifurcating into left and right bundle branches (Lbb & Rbb) down the two sides of inter-ventricular septum, LEE bifurcates into anterior and posterior divisions or fescicles.
Purkinje fibers: Network of fibers at end of bundle of His that transmits impulse to both ventricular walls.