1. List the elements of the intrinsic conduction system in order, starting from the SA node: SA Node-> AV node-> AV Bundle (bundle of his)->bundle branches-> purkinje fibers At what structure in the transmission sequence is the impulse temporarily delayed? Why? The AV node allows atrial contraction to be completed before ventricular systole begins. 2. Even though cardiac muscle has an inherent ability to beat, the nodal system plays a critical role in heart physiology. What is that role? Its main role implies depolarization and coordination of cardiac action.