Cardiac muscle is a type of muscle tissue found in which location?

• A. In the heart
• B. In voluntary control in limbs
• C. In the digestive tract
• D. In the skin

Answer: (A)

Cardiac muscle tissue forms the walls of the heart—the myocardium—and is specialized to contract rhythmically and involuntarily to pump blood. Its cells are branched and interconnected by intercalated discs with gap junctions and desmosomes, which allows the heart to beat as a coordinated unit. This automatic, self-regulating contraction is a hallmark of cardiac muscle, setting it apart from other muscle types. The muscles in the limbs are skeletal and under voluntary control, the digestive tract is lined with smooth muscle, and the skin does not contain cardiac muscle. So the heart is the correct location.