Final answer:
Electrical impulses from the AV node are transmitted via the Bundle of His and Purkinje fibers causing ventricular systole, which begins at the heart's apex and moves towards the base.
Step-by-step explanation:
When electrical impulses from the atrioventricular (AV) node are transmitted to the entire ventricular system, the Bundle of His and the Purkinje fibers transmit these impulses, resulting in ventricular systole or contraction from the bottom of the heart. This process begins with the impulse from the sinoatrial (SA) node causing the atria to contract, and following a pause at the AV node, the impulse is conducted to the ventricular myocardium. The contraction starts at the apex of the heart, moving upwards to efficiently pump out blood into the aorta and pulmonary trunk.