Which property allows cardiac muscle cells to contract without nerve stimulation?

The property that allows cardiac muscle cells to contract without nerve stimulation is automaticity. Cardiac muscle cells, specifically those in the sinoatrial (SA) node, have the unique ability to generate their own electrical impulses due to the presence of specialized pacemaker cells. This intrinsic ability means that they can spontaneously depolarize and initiate action potentials, leading to muscle contraction.

Automaticity is essential for maintaining a rhythmic and coordinated heartbeat, independent of external nerve signals. This characteristic is crucial for the heart's autonomic function, allowing it to respond to the body's changing demands for blood flow without requiring direct nerve input every time a contraction occurs. This self-stimulation is vital for sustaining life, as it ensures that the heart continues to beat effectively even when it is disconnected from the nervous system or when nerve signals are impaired.