There are three primary types of muscle. Cardiac muscle is composed of striated, mono-nucleated cells and is found in the heart. Additionally, cardiac muscle cells are joined by intercalated discs and are capable of auto-regulating contraction without nervous stimulation.

Skeletal muscle is composed of striated, multinucleated cells and is found around the bones of the body. Skeletal muscle is under voluntary control and is primarily responsible for causing movement of bones and limbs.

Smooth muscle is composed of non-striated, mono-nucleated cells and is found around the organs and blood vessels of the body. Smooth muscle helps control blood flow, digest food, and contract the diaphragm.

Skeletal muscle is striated due to its sarcomere composition. The bands of each sarcomere align, giving the muscle its striped appearance. Skeletal muscle cells have multiple nuclei, allowing them to synthesize more RNA (and proteins) to maintain muscle tone.

Intercalated discs are only found in cardiac muscle, and help with cell adhesion and signal transduction.

Cardiac muscle cells are involuntarily controlled: we cannot consciously control how fast our heart beats. The muscle cells are composed of aligned sarcomeres, so they appear striated, or striped. They have intercalated discs, which allow action potentials to spread between muscle cells in the heart.

Cardiac muscle cells are not multinucleated; skeletal muscle cells, however, do have multiple nuclei.

There are three types of muscle tissue. Cardiac muscle is found in the heart, smooth muscle surrounds organs and blood vessels, and skeletal muscle is used to move the skeleton and body.

During periods of heavy exercise, it is the cardiac muscle and skeletal muscles that get worked out. Cardiac muscle is strengthened because it has to pump more oxygenated blood to the body, while skeletal muscles are the muscles we move in order to exercise.

Smooth muscle is not directly related to exercise.

Skeletal muscle is a form of striated muscle under the control of the somatic nervous system (voluntary control). Skeletal muscle is striated and contains multiple nuclei.

Smooth muscle is a component of the inner lining of different organs and blood vessels. Smooth muscle is not striated and is mononucleated.

Cardiac muscle is the muscle that allows the heart to contract, thereby pumping blood throughout the body. Cardiac muscle is striated and mononucleated.

This is the correct order because in every muscle fiber there are many myofibrils, and in every myofibril there are many myofilaments. The two main myofilaments are the proteins actin and myosin.

The three types of muscle tissues are: skeletal, cardiac, and smooth. Epithelial tissue is another of the four tissues found in animals, and is responsible for lining body cavities, forming glands, and covering the body (skin). The two other basic animal tissue types are connective, and nervous.