Work Step by Step
Option A is incorrect. The heartbeat is generated in the heart tissue itself. Option C is incorrect. The atrioventricular node picks up the impulse from the sinoatrial node and initiates contractions in the ventricles following a short pause. Option D is incorrect. The aorta is the largest artery in the body and does not have anything to do with a heartbeat. Option B is correct. The sinoatrial or SA node is known as the pacemaker. It is a collective of cardiac muscle fibers that initiate the impulse that spreads throughout the atria, causing the atria to contract simultaneously.