Abbreviation: SA node
The pacemaker of the heart. Located in the right atrium adjacent to the opening of the superior vena cava. Composed of specialized pacemaker cells that spontaneously generate action potentials, which are converted to electrical impulses that are conducted to the myocardium through a specialized pathway, which results in myocardial contraction. Generates impulses at the rate of ~ 60–100/min in adults.