What are the valves in alimentary canal?

Answer 1

The gastrointestinal tract is equipped at critical junctures with a number of muscular valves, or sphincters , which, usually under the direction of the autonomic nervous system, can regulate the movement of food through the digestive tube. Another function of a sphincter is to prevent backflow of partially digested food.The first of these pursestring valves occurs at the cardia , the opening where the esophagus meets the stomach, and is called the cardiac sphincter , from its location almost directly in front of the heart. Another important muscle ring is the pyloric sphincter , at the opening called the pylorus , located at the other end of the stomach, at the connection between stomach and small intestine. The release of waste from the rectum is controlled, partly voluntarily, by an anal sphincter , located at the anus , which marks the end of the tract.