THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The sinus node continuously generates electrical impulses, thereby setting the normal rhythm and rate in a healthy heart. Hence, the SA node is referred to as the natural pacemaker of the heart.

Detailed explanation-2: -Cardiac Pacemaker Cells Are Specialized Cardiomyocytes With a Distinct Gene Expression Program. Pacemaker cells comprise a small population of specialized cardiomyocytes within the sinoatrial node (SAN) that spontaneously fire to trigger each heartbeat.

Detailed explanation-3: -The sinoatrial node (SAN) is the dominant pacemaker of the heart, located at the junction of the superior vena cava and right atria, that regulates heart beat frequency [1].

Detailed explanation-4: -The pacemaker cells can also respond to various hormones that modulate heart rate to control blood pressure. There are two major types of cardiac muscle cells: myocardial contractile cells and myocardial conducting cells.