Final answer:
The natural pacemaker of the heart is the sinoatrial (SA) node, which generates electrical impulses to maintain a regular heart rate. When issues arise, an artificial pacemaker may be implanted to ensure the heart's rhythm is maintained.
Step-by-step explanation:
The part of the heart that serves as the natural pacemaker is the sinoatrial (SA) node. This is a specialized group of cells located in the right atrium of the heart. The SA node generates electrical impulses that initiate the sinus rhythm, causing the heart to beat at a regular pace. When the SA node functions properly, it ensures that the heart's chambers contract in an orderly sequence, promoting efficient blood flow through the heart and into the circulatory system.
If there is a problem with the heart's natural pacemaker, such as an arrhythmia becoming chronic, a medical device called an artificial pacemaker may be necessary. This device delivers precise electrical impulses to the heart muscle, which can either be programmed to work on demand or continuously, and may also include a built-in defibrillator. The SA node's inherent rate of depolarization is the highest within the heart, establishing it as the predominant pacemaker.