Which muscle tissue is found only in the heart?

• A. Skeletal
• B. Nervous
• C. Cardiac
• D. Smooth

Answer: (C)

The concept being tested is recognizing the different muscle tissue types by where they occur and how they behave. Cardiac muscle tissue is found only in the heart, making it unique among the muscle types. It looks striated like skeletal muscle, but it contract involuntarily and is specialized for continuous, rhythmic beating. Its cells are connected by intercalated discs, which contain gap junctions and desmosomes to coordinate heart contractions quickly and firmly.

Skeletal muscle attaches to bones and is under conscious control, enabling voluntary movements. Smooth muscle lines the walls of hollow organs and blood vessels and operates involuntarily to move substances through organs. Because only cardiac muscle tissue resides in the heart, it is the specific tissue described in the question.