 Dear students, in this topic, we shall discuss the process of peristalsis in detail. Peristalsis involves the continuous contractions and relaxations of circular and longitudinal muscles of the alimentary canal, which produce alternating waves of constriction and distension in the lumen. Peristalsis starts from the buccal cavity and continues along the length of esophagus to the stomach and then along the whole of the intestine till the rectum. It is a buccal cavity that starts with a muscular wave that continues till the end of the rectum. This is called peristalsis. Dear students, peristalsis depends on the arrangement of smooth muscles in the alimentary canal wall. The alimentary smooth musculature consists of an inner circular layer of smooth muscles and an outer longitudinal layer of smooth muscles. When the inner circular layer contracts, outer longitudinal layer relaxes. This coordination produces constriction in the lumen. When the inner longitudinal layer contracts and the circular layer relaxes, the distension of the lumen wall is produced. Dear students, peristalsis pushes the food along the alimentary canal from the mouth to the anus. Food's movement direction is dependent on the direction of peristaltic wave. If the direction of peristalsis moves from the buccal cavity to the anus, the food moves to the anus. Peristalsis induces swallowing, which means the food is ingested and it culminates in defecation. Dear students, if the direction of peristalsis reverses, it is called reverse peristalsis. As a result of reverse peristalsis, the luminal contents, they come back into the buccal cavity. Eat mammals have a common and normal process in which they can regurgitate their food, that is, bring up the undigested or un-chewed food for further chewing in the buccal cavity. In other animals, if this process occurs, it results in vomiting or amesis.