American Academy of Professional Coders (AAPC) Practice Exam

Which type of muscle is responsible for involuntary movements in the heart?

1. Skeletal muscle

2. Cardiac muscle

3. Smooth muscle

4. Voluntary muscle

The correct answer is: Cardiac muscle

Cardiac muscle is specifically designed to facilitate involuntary movements within the heart. It makes up the walls of the heart and is responsible for the contraction and relaxation that pump blood throughout the body. This type of muscle operates automatically, meaning it does not require conscious thought or effort to function. Cardiac muscle has unique characteristics that distinguish it from other types of muscle. For instance, it is striated like skeletal muscle, but it is controlled involuntarily, much like smooth muscle, which is found in various organs and controls movements such as digestion. However, skeletal muscle, which is under voluntary control, is responsible for movements of the skeleton and body that one consciously decides to perform. Overall, the unique properties and specific location of cardiac muscle make it the specialized muscle type responsible for the essential involuntary movements of the heart.