Which structure begins the impulse conduction of the heart?

The sinoatrial (SA) node is the structure that initiates the impulse conduction of the heart. It is commonly referred to as the heart's natural pacemaker. Located in the right atrium, the SA node generates electrical impulses that lead to the contraction of the heart muscle, specifically the atria, which is essential for maintaining an effective heartbeat.

When the SA node fires, it sends out an electrical signal that spreads across the atria, causing them to contract and push blood into the ventricles. After this, the impulse is transmitted to the atrioventricular (AV) node, which serves as a relay point before sending the signal down to the ventricles through the bundle of His and Purkinje fibers. This coordinated sequence ensures that the heart beats in a synchronized and effective manner.

As a result of this natural pacing mechanism, the SA node is fundamental for initiating the cardiac cycle and establishing the heart rhythm. Understanding its role is crucial for recognizing how other components of the heart's conduction system function in response to the impulses generated by the SA node.