Sinoatrial node

Sinoatrial node (also known as SA node) is the natural pacemaker of the heart. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava. These cells are responsible for initiating each heartbeat.

Anatomy

The SA node is located in the superior part of the right atrium, near the opening of the Superior vena cava. It is a crescent-shaped structure that measures approximately 3 mm in width, 15 mm in length, and 1 mm in thickness.

Function

The primary function of the SA node is to generate electrical impulses that initiate the heartbeat. These impulses are then transmitted to the atrioventricular (AV) node, which serves as a gateway to the ventricles.

Clinical significance

Dysfunction of the SA node can lead to various arrhythmias, such as sinus bradycardia, sinus tachycardia, and sick sinus syndrome. Treatment options for SA node dysfunction include medication and the implantation of a pacemaker.

See also

• Cardiac pacemaker
• Electrical conduction system of the heart
• Heart

References

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  Sinoatrial node
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  Sinoatrial node low magnification
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  Sinoatrial action potential
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  Sinoatrial node
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  Sinoatrial node