Skeletal muscles Structure; they are long cylindrical fiber, striated, many peripherally located nuclei. Functions; Voluntary movement, produces heat, protects organs. Examples; the biceps, slow twitch fibers, fast glycolytic fibers. Cardiac muscles Structure; they are short, branched, striated, single central nucleus Functions; Contracts to pump blood, they are found in the heart Examples; Heart muscles Smooth muscles Structure; They are short, spindle shaped, no evident of striation, single nucleus in each fiber Function; Involuntary movement, moves food, involuntary control of respiration, moves secretions, regulates the flow of blood in arteries by contraction. Example; Muscles found in the walls of hollow organs like the intestines, stomach and the blood vessels.