The heart muscle that contracts to pump blood is?

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

Answer: (A)

Identifying which tissue in the heart produces its pumping action. The heart’s pumping force comes from cardiac muscle, the myocardium, a specialized involuntary tissue that contracts rhythmically. Cardiac muscle fibers are connected by intercalated discs with gap junctions, creating a functional syncytium that coordinates a strong, synchronized squeeze to eject blood during systole. Skeletal muscle is attached to bones and under voluntary control, so it does not form the heart’s pumping action. Smooth muscle lines the walls of vessels and organs and regulates flow, but it isn’t the muscle that drives the heart’s beat. Fibrous tissue is non-contractile connective tissue, so it cannot contract to pump blood.