Ans. Digestion is regulated by smooth muscles in the GI tract also called the gastrointestinal tract. The GI tract is long and runs throughout the body, i.e from the mouth to the anus.In a wave-like movement called peristalsis, food travels via the digestive system. In order to induce this movement, muscles present in the membranes of the empty organ cause regular contraction and relaxation, which forces food into the stomach via the esophagus.