Digestion
A burger is broken down mechanically by biting into it. The food in the mouth sets off salivary glands that secrete salivary amylase, which breaks down amylase in the burger. When the food is broken down enough, the tongue shapes the food in a bolus, or a ball. The bolus is pushed back to the pharynx at the back of the throat. The food stimulates the opening of the flap so the good goes down the esophagus, rather than the windpipe. Because of peristalsis, rhythmic waves created by muscles in the throat, the food slides easily down the digestive tract. …
