Conduction system of the heart

Conduction System of the Heart

The conduction system of the heart is a group of specialized cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components of the heart's electrical system are the sinoatrial node (SA node), atrioventricular node (AV node), bundle of His, bundle branches, and Purkinje fibers. This system ensures the coordinated heartbeat necessary for effective pumping of blood throughout the body.

Components

Sinoatrial Node

The sinoatrial node (SA node) is often referred to as the heart's natural pacemaker. It is located in the right atrium of the heart. The SA node generates electrical impulses that are propagated throughout the atria, causing them to contract and push blood into the ventricles.

Atrioventricular Node

The atrioventricular node (AV node) is situated at the junction between the atria and the ventricles. It acts as a gate that slows the electrical signal before it enters the ventricles. This delay ensures that the atria have enough time to contract and fill the ventricles with blood before they themselves contract.

Bundle of His

The bundle of His is a collection of heart muscle cells specialized for electrical conduction. It transmits the electrical impulses from the AV node to the bundle branches. It is located in the interventricular septum.

Bundle Branches

The bundle branches are part of the conduction system that extend from the bundle of His into the right and left ventricles. They further divide into Purkinje fibers that spread throughout the ventricles, ensuring coordinated contraction of the ventricular muscle.

Purkinje Fibers

Purkinje fibers are specialized conductive fibers located within the walls of the ventricles. They are responsible for the rapid conduction of electrical impulses throughout the ventricles, leading to their simultaneous contraction and efficient pumping of blood to the lungs and the rest of the body.

Function

The primary function of the conduction system is to maintain a consistent heart rate and rhythm that adjusts according to the body's needs. It does this by generating and transmitting electrical impulses that stimulate the heart to contract in a coordinated manner.

Clinical Significance

Disorders of the conduction system can lead to arrhythmias, which are problems with the rate or rhythm of the heartbeat. Examples include atrial fibrillation, bradycardia, and tachycardia. Treatment may involve medication, pacemaker implantation, or other interventions to manage the heart rhythm.

See Also

• Cardiac electrophysiology
• Electrocardiogram
• Heart
• Cardiac cycle