CVS Practice Test

What defines the term 'autorhythmicity' in the context of cardiac muscle?

1. Ability to contract forcefully

2. Ability to depolarize regularly

3. Ability to generate action potentials

4. Ability to remain at resting potential

The correct answer is: Ability to depolarize regularly

The term 'autorhythmicity' in the context of cardiac muscle refers specifically to the ability of certain cardiac cells, primarily in the sinoatrial (SA) node, to depolarize regularly without the need for external stimuli. This intrinsic characteristic allows the heart to maintain a consistent rhythm and assures that it can initiate contractions at a regular pace, functioning as the natural pacemaker of the heart. This regular depolarization is crucial for the heart's ability to beat rhythmically and efficiently. The cells in the SA node spontaneously generate action potentials, which then propagate through the heart muscle, leading to coordinated contractions. Understanding autorhythmicity is key to grasping how the heart regulates its own heartbeat independently of external signals. Thus, the correct answer underscores this essential quality that defines how the heart can continuously and automatically generate rhythmic contractions, setting the stage for its overall function in the cardiovascular system.