Chewing food carefully is important in order for the digestive system to function properly. Saliva, which contains amylase, is excreted in the mouth while you chew food. Amylase is an enzyme that begins to break down carbohydrates. The longer the food is chewed in the mouth, the more amylase is produced. For example, if you keep a piece of sourdough bread in your mouth for a long time, you will notice that it starts to taste sweet. When this happens, the amylase has chopped the bread up into smaller carbohydrates that taste sweeter than the original, larger carbohydrates did.

The function of the esophagus is to transport food and fluid from the mouth to the stomach. At the same time, the epiglottis flips down to prevent food from entering the trachea.

The series of illustrations below displays the swallowing reflex. In the first image, the epiglottis allows air to flow into the trachea. In the second image, the epiglottis flips down. In the final image, the food is swallowed and the air enters the trachea again.

Food passes through the esophagus in a few seconds. The walls of the esophagus contain smooth muscle tissue that carries food downward by contracting. Sometimes you can feel how poorly chewed or dry pieces of food can get stuck in your esophagus. When you rinse the esophagus by drinking liquid, you will feel the liquid level inside your esophagus rise. The nasty feeling eases as the stuck food passes forward into the stomach.

Swallowing is a reflex.