The tertiary pacemaker of the heart is commonly referred to as?

The tertiary pacemaker of the heart is commonly referred to as the Purkinje fibers. In the hierarchy of cardiac conduction, the heart has a primary pacemaker (the SA node), a secondary pacemaker (the AV node), and a tertiary pacemaker (the Purkinje fibers).

The SA node is responsible for initiating the heartbeat and setting the rhythm, making it the primary pacemaker. The AV node acts as a relay point, slowing down the conduction to ensure the atria contract before the ventricles, which serves as a secondary pacemaker in case the SA node fails. However, if both the SA and AV nodes fail to produce impulses, the Purkinje fibers take over as the tertiary pacemaker to maintain a basic rhythm, albeit at a slower rate than the primary and secondary pacemakers.

Understanding this hierarchy is essential for grasping how the heart maintains rhythm and how each structure can act in cases of failure of the upstream pacemakers. Existing knowledge that the Purkinje fibers can generate impulses is key to recognizing their role in this context.