Smooth muscle cells are spindle shaped and contain a single nucleus. Smooth muscle is under involuntary control. Cardiac muscle tissue is only found in the heart. Cardiac muscle cells are branched, contain a single nucleus and are joined by intercalated discs. Cardiac muscle tissue is under involuntary control.
Movement is the result of the actions of muscles on bones.
Tendons attach most skeletal muscles to bones, allowing muscle contraction to move the bones across a joint. Most of the cell is occupied by striated, thread-like myofibrils. Within each myofibril there are dense Z lines. Each sarcomere has thick and thin filaments. The thick filaments are made of myosin and occupy the center of each sarcomere.