American Academy of Professional Coders (AAPC) Practice Exam

What type of muscle is primarily found in the heart?

1. Skeletal muscle

2. Cardiac muscle

3. Smooth muscle

4. Striated muscle

The correct answer is: Cardiac muscle

The type of muscle primarily found in the heart is cardiac muscle. This specialized type of muscle tissue is unique to the heart and is responsible for pumping blood throughout the body. Cardiac muscle cells, or cardiomyocytes, are interconnected by intercalated discs, which facilitate the rapid transmission of electrical impulses—essential for the synchronized contraction of the heart. Unlike skeletal muscle, which is under voluntary control and composed of long, striated fibers, cardiac muscle works involuntarily and has a branched structure. Although cardiac muscle is also striated, it differs significantly in function and structure from skeletal muscle. Smooth muscle, found in walls of hollow organs such as the intestines and blood vessels, operates involuntarily and does not have striations. While striated muscle might refer to both skeletal and cardiac muscle in a broad sense, the specific term that accurately describes the muscle of the heart is cardiac muscle.