Which type of muscle makes up the heart?

• A. Skeletal muscle
• B. Cardiac muscle
• C. Smooth muscle
• D. Myocardial tissue

Answer: (B)

The heart is composed of cardiac muscle, a specialized muscle tissue that forms the myocardium. Cardiac muscle is unique because it contracts involuntarily and in a highly coordinated way thanks to intercalated discs that link the cells and allow them to beat as one unit. This synchronized contraction is essential for pumping blood continuously throughout life. Skeletal muscle is attached to bones and moves limbs, while smooth muscle lines hollow organs and vessels and contracts more slowly and involuntarily but not in the rhythmic, forceful way the heart requires. While some sources use the term myocardial tissue, the standard label for the heart’s muscle is cardiac muscle, making it the correct choice.