Cardiac Pacemaker Location: SA Node vs. Other Heart Structures

The primary cardiac pacemaker is the SA node, located in the right atrium near the superior vena cava entrance. It generates electrical impulses causing heart contraction.

Other structures:

• AV node: At atrioventricular junction; delays impulses to allow atrial filling before ventricular contraction.
• Atrioventricular bundle: Conducts impulses from AV node to ventricles.
• Left atrium: Receives oxygenated blood from lungs.