Muscle tissue is composed of long and excitable cells that have the capability of contraction. The micro-filaments actin and myosin are parallel within the cytoplasm, creating a striated look to the muscle tissue. Muscle is the most abundant tissue in animals, accounting for almost two-thirds of the bulk. The three types of muscle tissue are cardiac, skeletal, and visceral. Attached by tendons, skeletal muscle is responsible for most voluntary movements of the body.
Skeletal muscle is called striated, because it has a striped apearance from overlaping filaments.
Cardiac muscle makes up the contractile wall of the heart it is striated and branched. The ends of the cells are attached to intercalculated discs, that relay the contract signal from the individual cells during a heart beat. Visceral or smooth muscle is not striated, and is in the walls of internal organs. The cells are spindle shaped, and can mantain their contracted form longer than skeletal muscle. This form of muscle contraction is involuntary.