In a chicken, striated muscle controls locomotion. These muscles are directed by the central nervous system to allow it to walk, jump, run and fly. This muscle is attached to parts of the skeleton by connective tissue. Smooth muscle, which is an involuntary muscle is used in places such as the esophagus and gizzard to first move food into the digestive system and then through contractions grinds the food allowing it to move into the intestine where again, smooth muscle is employed to push food through the system. Smooth muscle is also present in the chickens blood vessels which expand and contract to regulate blood pressure. Finally, cardiac muscle is found in the heart and contracts to force blood throughout the system.