Final answer:
The heart's ability to generate its own electrical impulse is known as autorhythmicity, which is an intrinsic property of the cardiac muscle that allows for self-regulated depolarization and action potential fires that set the heart rate.
Step-by-step explanation:
The heart's ability to generate its own electrical impulse is known as autorhythmicity. This intrinsic capability allows cardiac muscle to initiate its own electrical impulse that triggers the mechanical contraction that pumps blood at a fixed pace without nervous or endocrine control. The conduction system of the heart includes the sinoatrial node, the atrioventricular node, the atrioventricular bundle, the atrioventricular bundle branches, and the Purkinje cells, which are responsible for this autorhythmic function. These cells are able to depolarize to threshold and fire action potentials on their own at set intervals, which determine the heart rate. This feature is crucial for the coordination of the heart's functional syncytium, allowing the wave of contraction to spread through the pacemaker cells and across the connected muscle fibers in a unified manner.