... it easier for the food to be digested, called saliva which contains the enzyme salivary amylase and this comes from the salivary gland. This enzyme begins the digestion of carbohydrates in the food by breaking down starch, from the bread, into maltase. This process is chemical digestion. After this the food is taken down a long tube, called the oesophagus, which takes the food from the mouth to the stomach. The movement of the food is helped by waves of contraction of the muscle surrounding the oesophagus, this is called peristalsis. Once the food enters the stomach a ring of muscle at the exit called the pyloric sphincter contracts and prevents the food from leaving. For the next two to three hours churning movements of the stomach produce further physical breakdown of food. The only chemical digestion that takes place in the stomach is the breakdown of proteins, which is ...

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