After the electrical impulse goes through the AV Node, the electrical impulse will go through the "conduction system" of the ventricle. Conduction means heat or electricity traveling through something. This brings the electrical impulse to the ventricles. The first part of the conduction system is the "bundle of His". "His" is named for the doctor (Wilhelm His, Jr) who discovered it. Bundle means strings or wires grouped together in parallel. Once the bundle ("meaning a group of strings or wires going in parallel directions") goes through the ventricle muscle, it divides into two "bundle branches", the left bundle branch and the right bundle branch. The left bundle branch travels to the left ventricle and the right bundle branch travels to the right ventricle. At the end of the bundle branches, the electrical impulse goes into the ventricular muscle through the Purkinje Fibers. This is what makes ventricle contraction take place and makes ventricular systole.