Home » Heart and Blood Vessel Basics » Your Heart's Electrical System
What Is the Electrical System in Your Heart?The electrical system in your heart controls the speed of your heartbeat. The system includes a network of electrical pathways, similar to the electrical wiring in your home. The pathways carry electrical signals through your heart. The movement of the signals is what makes your heart beat. When working properly, your heart's electrical system automatically responds to your body's changing need for oxygen. It speeds up your heart rate as you climb stairs, for example, and slows it down when you sleep. When your heart rate speeds up, it means your heart pumps faster and your body gets more oxygen-rich blood. Your heart's electrical system is also called the cardiac conduction system. Parts of the Electrical SystemYour heart's electrical system includes three important parts (Figure 1): S-A node (sinoatrial node)
A-V node (atrioventricular node)
His-Purkinje system
Figure 1
The S-A Node: Your Heart's Natural PacemakerThe S-A node is a bundle of specialized cells in your right atrium. The S-A node cells are special because they create the electricity that makes your heart beat. The S-A node normally produces 60-100 electrical signals per minute — this is your heart rate, or pulse. The S-A node is called the "natural pacemaker" of your heart because it controls your heart rate. The A-V Node: Your Heart's Electrical BridgeThe A-V node is a bundle of specialized cells between your heart's upper and lower chambers (between the atria and ventricles). The A-V node cells are special because they allow electricity to pass through them. Except in rare conditions, no other cells between the atria and ventricles allow this. So, the A-V node is the "electrical bridge" between the atria and ventricles. Some types of slow heart rhythms (bradycardias) are caused by problems in the A-V node. The His-Purkinje SystemThe His-Purkinje system is in your heart's ventricles. Electricity travels through the His-Purkinje system to make your ventricles contract. The parts of the His-Purkinje system include: His Bundle (the start of the system)
Right bundle branch
Left bundle branch
Purkinje fibers (the end of the system)
|
|
Q. What is the natural pacemaker of your heart? His bundle A-V node S-A node
Q. How does electricity get from the upper to the lower chambers of your heart? Through the His-Purkinje system Through the A-V node Through the S-A node
|
