Each Heartbeat is Initiated by the _______

Question

Each heartbeat is initiated by the _______.
A) sinoatrial (SA) node
B) atrioventricular (AV) bundle
C) AV node
D) sinoventricular bundle

Accepted Answer

The sinoatrial (SA) node, located in the right atrium, is the natural pacemaker of the heart and initiates each heartbeat by sending electrical impulses to the atria, causing them to contract. This electrical signal then travels to the atrioventricular (AV) node, which serves to delay the signal slightly before sending it down the AV bundle (also known as the bundle of His) and through the Purkinje fibers, leading to the contraction of the ventricles.