Florida Basic Recruit Training Program High Liability (First Aid) Practice Exam

Which muscles are unique in that they are found only in the heart?

1. Involuntary muscles

2. Skeletal muscles

3. Cardiac muscles

4. Voluntary muscles

The correct answer is: Cardiac muscles

Cardiac muscles are unique because they are specifically found only in the heart. This type of muscle is specialized for the continuous, rhythmic contraction necessary to pump blood throughout the body. Cardiac muscle fibers are striated, much like skeletal muscles, but they differ in that they are involuntary and not under conscious control. This involuntary nature allows the heart to function independently of the nervous system, though it can still be influenced by things such as hormones and the autonomic nervous system. Other types of muscles, like skeletal and voluntary muscles, are found throughout the body and are primarily involved in movement and stability of the skeletal system. In contrast, involuntary muscles are a broader category that includes smooth muscles as well as cardiac muscles; however, only cardiac muscles are exclusive to the heart. Thus, the heart's unique structure and function are attributed specifically to cardiac muscle tissue.