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 …showed first 75 words of 365 total…

…showed last 75 words of 365 total…has a very large surface area because villi, or finger like projections on the surface, contain microvilli, smaller projections on the surface of the villi. Because of this, the surface area of the small intestine is greatly increased. The large intestine, or colon, has the job of retaining water. It reabsorbs water and nutrients that remain in the lumen. The undigested materials are then excreted in feces, and the digestion of the burger is completed.