ACSM Personal Trainer Certification Practice Exam

What is a characteristic of cardiac muscle tissue?

1. It can function without nervous system input

2. It is responsible for voluntary movements

3. It primarily forms ligaments and tendons

4. It has an external control for contraction

The correct answer is: It can function without nervous system input

Cardiac muscle tissue has a distinct ability to function without direct input from the nervous system, which is a defining characteristic. This tissue is inherently capable of generating its own electrical impulses due to its specialized cells, known as pacemaker cells. These cells initiate contractions and coordinate the heartbeat autonomously, allowing the heart to pump blood effectively even if the nerves that typically stimulate it are severed or damaged. This characteristic distinguishes cardiac muscle from skeletal muscle, which relies on neurological input for movement and contractions. Additionally, unlike ligaments and tendons, which are composed of connective tissue, cardiac muscle is specialized for the rhythmic contraction and relaxation necessary for heart function. Lastly, while there are influences from the nervous system that can modulate heart rate and strength of contraction, the intrinsic ability of cardiac muscle to contract without such input is critical for its function as a pump.