AEMCA Practice Exam

For the heart to beat, must there be a nerve impulse from the nervous system?

1. Yes, always required

2. No, the heart has its own system

3. Only in emergencies

4. Only in infants

The correct answer is: No, the heart has its own system

The heart has its own intrinsic conduction system that allows it to beat independently of direct nerve impulses from the nervous system. This system is primarily driven by specialized cardiac cells located in the sinoatrial (SA) node, which generates electrical impulses that trigger heartbeats. This built-in ability ensures that the heart can maintain a consistent and rhythmic pace essential for circulation, even in the absence of external nervous stimulation. While the autonomic nervous system can modulate the heart rate in response to various physiological conditions (such as stress or changes in activity level), it is not necessary for the initiation of each heartbeat. This fundamental characteristic distinguishes the cardiac muscles from other types of muscles, which typically rely on nervous impulses for contraction.