Which muscle is found in the heart?

• A. Cardiac muscle
• B. Skeletal muscle
• C. Smooth muscle
• D. Voluntary muscle

Answer: (A)

Cardiac muscle is the muscle found in the heart. It’s a specialized, involuntary muscle tissue that forms the heart walls and contracts automatically to pump blood. Cardiac muscle cells are connected end-to-end by intercalated discs, which allow electrical signals to pass quickly and keep the heart beating in a coordinated, rhythmic way. This automatic, self-sustaining contraction is a defining feature that sets it apart from other muscle types.

Skeletal muscle, by contrast, is the voluntary, attached-to-bones muscle that you can consciously contract to move your body. Smooth muscle lines the walls of hollow organs and blood vessels and contracts without conscious control, but it is not striated like cardiac muscle. The term voluntary muscle usually refers to skeletal muscle, not the heart. So the muscle you find in the heart is cardiac muscle.