The Sino-Atrial node

The sino-atrial (SA) node is the heart’s natural pacemaker. This node is a small, oval-shaped structure located in the lateral wall of the right atrium, near the opening of the superior caval vein.

The cells of the SA-node are capable of generating action potentials autonomously. Once an action potential, also known as a cardiac impulse, has been generated in the SA-node, adjacent cells of the right atrium are activated (or depolarized). Consequently, the whole atrial syncytium depolarizes.


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