Carla was startled by an extremely loud bang that sounded li…

Carla was startled by an extremely loud bang that sounded like a gunshot. Her heartbeat accelerated rapidly. When she found that the noise was only a car backfiring, she felt greatly relieved but her heart kept beating heavily for over half an hour. Why did this happen?

Carla was startled by an extremely loud bang that sounded li…

Carla was startled by an extremely loud bang that sounded like a gunshot. Her heartbeat accelerated rapidly. When she found that the noise was only a car backfiring, she felt greatly relieved but her heart kept beating heavily for over half an hour. Why did this happen?