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The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximately 15 mm long, 3 mm wide, and 1 mm thick, located directly below and to the side of the superior vena ...
The atrioventricular (AV) node is a second cluster of specialized myocardial conductive cells, located in the inferior portion of the right atrium within the atrioventricular septum. The septum prevents the impulse from spreading directly to the ventricles without passing through the AV node.
It is a region of cardiac muscle on the wall of the upper right atrium near to the superior vena cava entrance. The cells that make up the SA node are specialized cardiomyocytes known as pacemaker cells that can spontaneously generate cardiac action potentials. These signals are propagated through the heart's electrical conduction system.
On the microscopic level, the wave of depolarization propagates to adjacent cells via gap junctions located on the intercalated disc. The heart is a functional syncytium as opposed to a skeletal muscle syncytium. In a functional syncytium, electrical impulses propagate freely between cells in every direction, so that the myocardium functions as ...
Located in the wall of the right atrium is a group of specialised cells, called the Sinoatrial node (SAN). These cells, unlike most other cells within the heart, can spontaneously produce action potentials. [5]
The normal resting heart rate is called the sinus rhythm, created and sustained by the sinoatrial node, a group of pacemaking cells found in the wall of the right atrium. Cells in the sinoatrial node do this by creating an action potential.
The right atrial appendage (lat: auricula atrii dextra) is located at the front upper surface of the right atrium. Looking from the front, the right atrial appendage appears wedge-shaped or triangular. Its base surrounds the superior vena cava. [6] The right atrial appendage is a pouch-like extension of the right atrium and is covered by a ...
The action potential passes along the cell membrane causing the cell to contract, therefore the activity of the sinoatrial node results in a resting heart rate of roughly 60–100 beats per minute. All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the ...