sinusknude

The sinusknude, also known as the sinoatrial node or SA node, is a specialized area of cardiac tissue located in the upper wall of the right atrium of the heart. It functions as the natural pacemaker of the heart, initiating the electrical impulses that cause the heart to contract and pump blood. These impulses originate spontaneously and regularly, typically at a rate of 60 to 100 beats per minute in a healthy adult at rest. The electrical signal generated by the sinusknude spreads through the atria, causing them to contract, and then travels to the atrioventricular node (AV node) which relays the signal to the ventricles, leading to their contraction. The consistent and rhythmic firing of the sinusknude is crucial for maintaining a regular heart rhythm. Its rate can be influenced by the autonomic nervous system, with the sympathetic nervous system increasing the heart rate and the parasympathetic nervous system slowing it down. Disruptions to the sinusknude's function can lead to various arrhythmias, such as sinus bradycardia (a slow heart rate) or sinus tachycardia (a fast heart rate), and in more severe cases, sinus node dysfunction can necessitate the implantation of an artificial pacemaker.