Final answer:
After the heart's resting phase, the sinoatrial (SA) node is the next structure in the cardiac conduction system to be stimulated, leading to the beginning of a new cardiac cycle.
Step-by-step explanation:
After the heart rests, the sinoatrial (SA) node will be stimulated next as the electrical impulse travels to the Purkinje fibers.
The cardiac conduction system controls the sequence of events that occurs during a heartbeat. The cycle begins with the SA node, often referred to as the heart's natural pacemaker, which generates an electrical impulse. This impulse spreads across the atria, causing them to contract and pump blood into the ventricles. The impulse then travels to the atrioventricular (AV) node where there is a brief delay. This delay ensures that the atria have time to fully contract before the ventricles begin their contraction.
Following this delay, the impulse moves through the atrioventricular bundle and bundle branches before reaching the Purkinje fibers, which further distribute the signal throughout the ventricles. This highly coordinated pathway leads to efficient ventricular contraction and blood ejection into the aorta and pulmonary trunk. Therefore, after a period of rest post-ventricular contraction, the cycle recommences with the SA node initiating another electrical impulse.