Which term describes the ability of cardiac muscle cells to contract without stimulation from the nervous system?

The correct term for the ability of cardiac muscle cells to contract without stimulation from the nervous system is automaticity. This property allows cardiac muscle cells, particularly those in the sinoatrial (SA) node, to generate their own electrical impulses, leading to spontaneous contraction. This intrinsic feature is crucial for maintaining the heart's rhythm and ensuring that it can function autonomously, independent of external signals.

Automaticity is essential for the heart's operation, as it enables continuous and rhythmic contractions necessary for effective blood circulation. This characteristic distinguishes cardiac muscle from other muscle types, such as skeletal muscle, which requires nervous stimulation to initiate contraction.

Autorhythmicity is often confused with automaticity; however, it more broadly refers to the ability of the heart to self-regulate its rhythm, encompassing aspects of pacemaker activity. The refractory period describes the time following an action potential when the heart muscle cannot respond to another stimulus, and electrophysiology involves the study of the electrical properties of biological cells and tissues, including those in the heart.