sinoatriaalinen

Sinoatriaalinen refers to the sinoatrial node, often abbreviated as the SA node. This specialized region of cardiac tissue is located in the upper wall of the right atrium of the heart. The SA node is considered the natural pacemaker of the heart. It initiates the electrical impulse that triggers the heart muscle to contract.

The sinoatrial node possesses intrinsic automaticity, meaning it can generate electrical impulses spontaneously without external stimulation. These impulses originate at a regular rate, typically between 60 and 100 beats per minute in a healthy adult at rest. The electrical signal generated by the SA node spreads through the atria, causing them to contract and pump blood into the ventricles.

Following atrial contraction, the impulse reaches the atrioventricular node (AV node), which delays the signal slightly before transmitting it to the ventricles. This delay is crucial as it allows the atria to empty completely before the ventricles contract. The coordinated electrical activity originating from the SA node and propagating through the heart's conduction system ensures efficient and regular pumping of blood throughout the body. Dysfunction of the SA node can lead to various arrhythmias, such as bradycardia (slow heart rate) or sick sinus syndrome, where the heart's natural pacemaker fails to function properly.