The Route of Food through the Digestive System The brain tells the mouth to produce the saliva to make it easier to swallow. The Amylase in the saliva begins to break down the carbohydrates in the food before it gets to the throat. The food then enters the esophagus through the sphincter, and the muscles in the contractions in the esophagus push the food along. The lower esophagus sphincter opens fast to let the food into the stomach. Glands in the stomach secrete acid, enzymes, and mucous that protects the stomach lining. Muscle contractions stir up the acid and enzymes, liquefying most of the food. The remainder is broken down in to a pasty solid substance. The stomach contents enter the small intestine through the duodenum, where it mixes
