Sinoatrial Node, Sa Node

The Sinoatrial Node (Sinoatrial Node, Sa Node) is the pacemaker (pacemaker) of the heart: a specific microsite in the heart muscle located in the upper wall of the right atrium near the entry of the vena cava into it. The fibers of the sinoatrial node are self-exciting; they contract rhythmically at a frequency of approximately 70 contractions per minute. The impulses arising after each contraction propagate through the cardiomyocytes of the atria and the fibers connecting the sinoatrial node to the atrioventricular node. The sinoatrial node is innervated by nerves of the autonomic nervous system; the impulses arising in it speed up or slow down the heart rate.

The sinoatrial node (Sa Node) is one of the key elements that ensures the rhythm of heart contractions and the normal functioning of the cardiovascular system. It is a microsection of the heart muscle located in the upper part of the right atrium, near the confluence of the vena cava. This node plays the role of a pacemaker (pacemaker), that is, it is self-exciting and rhythmically contracts with a frequency of about 70 beats per minute.

The fibers that make up the sinoatrial node have the ability to self-excite, which allows them to independently generate electrical impulses, which then spread through the atrial cells of the myocardium and through the fibers connecting the node with the atrioventricular system. The excitation generated by the sinoatrial node speeds up or slows down the heart rate depending on the body's needs and is regulated by nerve impulses from the autonomic nervous system.

The sinoatrial node plays an important role in maintaining healthy functioning of the cardiovascular system, and its dysfunction can lead to various heart diseases. Therefore, research and understanding of the operation of this node is of great importance for improving the diagnosis and treatment of cardiovascular diseases.

The sinus node is the main pacemaker of the heart along with the sinus node of the atrioventricular septum. This creates an impulse for a proper, regular heartbeat. It triggers contractions between the inside of the heart muscle, which causes the arterial ventricle to fill. Thus, SA node cells are not excitatory sinus cells. They control the rate of heartbeat. A controlled pulse of echo from the area that is closer to the roots of the nodes is generated by special woven fibers. This causes the cells to contract more frequently. This contraction pattern is called an action potential. The conduction of this electrical impulse travels forward through all the muscles of the heart. If the rhythm of impulses from the SA system is irregular, this rhythm will also become uneven. This may be a sign of arrhythmia. The sinoatrial node is responsible for the correct pulsation of the ventricular rhythm, associated with another physiological system responsible for generating contractions. It should be noted that the sinoatrial node has several specific cells that separate it from other cell types. These cells produce