What is the heart's electrical conduction pathway starting from the SA node?

The correct sequence of the heart's electrical conduction pathway begins with the SA node, which is responsible for initiating the heartbeat by generating electrical impulses. From the SA node, these impulses travel to the AV node, where they are momentarily delayed to allow the atria to fully contract and empty into the ventricles. This delay is crucial for effective heart function, as it ensures proper filling of the ventricles before they contract.

After passing through the AV node, the impulses move into the Bundle of His. This structure branches into the right and left bundle branches, which extend along the interventricular septum. Finally, the electrical signals reach the Purkinje fibers, which distribute the impulses throughout the ventricles, allowing them to contract and pump blood efficiently.

This pathway highlights the organized and sequential nature of the heart’s electrical conduction system, ensuring coordinated contractions of the atria and ventricles. Each component of the pathway plays a vital role in maintaining an efficient and effective heart rhythm. Understanding this sequence is essential for anyone studying or working with cardiac physiology, as it underpins the basic mechanisms of heart function and arrhythmias.