The structure of muscle tissue varies depending upon whether the muscle controls voluntary or involuntary movements, according to the National Cancer Institute. There are three types of muscle: skeletal, smooth and cardiac. Skeletal muscle is striated, smooth muscle is non-striated and cardiac muscle has characteristics of both.
Skeletal muscle is the muscle that attaches to the bones. These muscles control voluntary movements, or movement under conscious control. These muscle cells are arranged in bundles of nerve fibers. They produce short, intense contractions.
Smooth muscle controls involuntary movements in the internal organs. The individual cells are organized with a single central nucleus rather than in bundles of fibers. Smooth muscle contracts slowly and in a steady rhythm.
Cardiac muscle is the muscle that makes up the heart. It contracts involuntarily, but its cellular structure is organized in bundles like skeletal muscle. However, the bundles in cardiac muscle are arranged differently. Cardiac muscle creates strong, rhythmic contractions.