The atrioventricular (AV) node is a specialized structure within the heart that acts as a critical part of the heart's electrical conduction system. Located in the Koch triangle near the coronary sinus on the interatrial septum, it's essentially a gatekeeper between the atria and the ventricles.
Here's a more detailed breakdown:
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Location: The AV node resides within the Koch triangle, which is an anatomical area defined by the tendon of Todaro, the coronary sinus orifice, and the tricuspid valve. This precise location is crucial for its function.
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Function: The primary function of the AV node is to delay the electrical impulse traveling from the atria to the ventricles. This delay is vital because it allows the atria to contract and completely empty their blood into the ventricles before the ventricles contract. Without this delay, the atria and ventricles would contract simultaneously, reducing the heart's efficiency in pumping blood.
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Conduction Pathway: After the sinoatrial (SA) node (the heart's natural pacemaker) initiates an electrical impulse, this impulse travels through the atria. Upon reaching the AV node, the impulse is slowed down. It then passes through the Bundle of His, bundle branches, and Purkinje fibers to stimulate ventricular contraction.
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Blood Supply: Typically, the right coronary artery supplies blood to the AV node in individuals with a right-dominant heart. In those with left-dominant or co-dominant coronary circulation, the AV node may receive blood from the left circumflex artery.
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Importance: The AV node's function is essential for maintaining proper heart rhythm and efficient cardiac output. Dysfunction of the AV node can lead to various heart rhythm problems (arrhythmias), such as AV blocks, which can require medical intervention, including pacemaker implantation.
In summary, the AV node is a crucial component of the heart's electrical system, ensuring proper timing between atrial and ventricular contractions for optimal blood flow.
