What is the role of the internodal pathways?

• A. Pathways connecting SA Node and AV Node
• B. Pacemaker of ventricles
• C. Conduct impulses from AV Node to His-Purkinje
• D. Serve as accessory pathways causing reentry

Answer: (A)

Internodal pathways are the atrial conduction routes that connect the sinoatrial (SA) node to the atrioventricular (AV) node, allowing the impulse to travel quickly from the SA node to the AV node. This rapid conduction ensures the AV node receives the signal in a timely manner, so the atria contract and the subsequent delay at the AV node can properly coordinate ventricular filling. They are not responsible for pacing the ventricles—that role belongs to the ventricle conduction system (the His-Purkinje network) after the impulse passes through the AV node. They are also not accessory pathways that enable reentry; those aberrant bundles bypass the normal AV nodal route.