Which muscle type is located in the heart and is involuntary?

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

Answer: (B)

The muscle type in the heart that contracts automatically and without conscious effort is cardiac muscle. This tissue forms the walls of the heart and is responsible for the rhythmic pumping action that keeps blood moving through the circulatory system. Cardiac muscle cells are striated like skeletal muscle, but they are involuntary because their activity is controlled by the autonomic nervous system and the heart’s own pacemaker cells. The cells are connected by intercalated discs that allow electrical signals to spread quickly and coordinate a strong, synchronized heartbeat.

Ligaments are connective tissue, not muscle. Smooth muscle is involuntary and non-striated, found in the walls of hollow organs. Skeletal muscle is voluntary and striated, attached to bones to move the body.