What is the conducting system of the heart?

The conducting system is a network of specialized cardiac muscle fibers (not neurons) that initiates and conducts electrical impulses to coordinate the heartbeat.

What are the main components of the heart's conducting system?

The system has five key parts: Sinuatrial (SA) node (the pacemaker in the right atrium), Atrioventricular (AV) node (delays impulses in the interatrial septum), Atrioventricular bundle (of His) (splits into bundle branches), Right and Left Bundle Branches (travel along the septum), and Purkinje fibers (terminal branches for ventricular contraction).

How does the electrical impulse travel through the heart?

The impulse starts at the SA node, spreads across the atria, reaches the AV node, then travels via the AV bundle and bundle branches to the Purkinje fibers, causing papillary muscles and ventricles to contract in sequence.

What arteries supply the conducting system?

The right coronary artery supplies most of the system, including the SA node, AV node, and bundle of His. The left coronary artery supplies part of the left bundle branch.

What happens if the conducting system is damaged?

Damage (e.g., from ischemia) can cause arrhythmias (irregular rhythms) or bundle block, leading to heart block where atrial and ventricular rates dissociate.

What is the role of the SA node?

The SA node acts as the heart's pacemaker, generating impulses (~70/min) to initiate atrial contraction and set the heart rate.

How does the AV node function in the conducting system?

The AV node delays impulses (~0.11 sec) to allow the atria to empty before ventricular contraction. It can also generate impulses at ~60/min if needed.

Cardiac Conduction System – SA Node, AV Node & Purkinje

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