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What role does the atrioventricular node play in coordinating a heartbeat?

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Illustration of a human heart cross-section showing four chambers-left and right atria and ventricles-with labeled major blood vessels. An inset highlights cardiac muscle tissue, showing myocytes and intercalated disks. — human cardiovascular system The human heart is both a pump and a muscle. Its four chambers move blood efficiently, while cardiac muscle cells joined by intercalated disks synchronize each contraction.

The atrioventricular (AV) node is a specialized mass of tissue that plays a critical role in the heart's electrical conduction system, which coordinates the rhythmic contraction of the heart muscle.12

Its primary functions include:

Signal Propagation: It serves as a vital relay point in the heart's conducting system, receiving electrical impulses that originate in the sinoatrial (SA) node and propagating them toward the ventricles via the bundles of His and Purkinje fibers.23
Coordination: By facilitating the transmission of these impulses, the AV node helps ensure the synchronous activation and contraction of the heart chambers. Specifically, it assists in the sequence where atrial contraction is followed by ventricular contraction, which is essential for the efficient pumping of blood.23
Pacemaker Activity: Like the SA node, the AV node consists of specialized cardiac muscle cells capable of spontaneous depolarization. While the SA node typically sets the pace for the heart due to its faster intrinsic rate, the AV node remains an integral part of the system that generates and maintains the heart's rhythmic electrical activity.3