Final answer:
The human heart requires two key systems to produce a heartbeat: the electrical conduction system that generates and transmits electrical signals, and the muscular pumping system that allows for the heart's contraction and relaxation, facilitating blood circulation.
Step-by-step explanation:
The two systems of the human heart that must be functional to produce a heartbeat are the electrical conduction system and the muscular pumping system. The electrical conduction system includes components such as the sinoatrial (SA) node, atrioventricular (AV) node, the bundle of His, right and left bundle branches, and the Purkinje fibers. This system generates and conducts electrical signals that initiate contraction of the heart muscle. The muscular pumping system involves the cardiomyocytes, which are the muscle cells responsible for contracting and pumping blood through the heart and into the circulation.
When the SA node generates an electrical charge, it causes the two atria to contract synchronously, leading to the movement of blood into the ventricles. After a brief pause at the AV node, the signal proceeds to the ventricles via the bundle of His and the Purkinje fibers, causing ventricular contraction. This orchestrated sequence allows the heart to effectively move blood during the systole (contraction) and diastole (relaxation) phases of the heartbeat.