Investigation of an isolated cardiac myocyte determined that it does not generate excitation impulses automatically, which means this cardiac myocyte was obtained from the following cardiac structure:

Answer options

1. Ventricles
2. Sinoatrial node
3. His’ bundle
4. Purkinje’s fibers
5. Atrioventricular node

Explanation

Automaticity is the property of cardiac cells to generate spontaneous action potentials the sinoatrial (SA) node normally displays the highest intrinsic rate. Atrial and ventricular myocardial cells do not display spontaneous diastolic depolarization or automaticity under normal conditions.