BTEC Level 3 Animal Management – Animal Biology Practice Test

The AV node is part of the heart’s electrical conduction route and sits in the right atrium, in the lower part of the interatrial septum near the opening of the coronary sinus. This location is within what’s called Koch’s triangle, and it lies close to the tricuspid valve. This placement lets the impulse travel from the atria to the ventricles but with a small delay, allowing the ventricles time to fill before they contract.

The sinoatrial node, by contrast, is located in the wall of the right atrium near the entry of the superior vena cava and acts as the primary pacemaker. Pulmonary circuit and systemic circuit are types of blood flow pathways, not specific anatomical nodes.