Food enters the digestive system through the mouth, where it is masticated (chewed) and begins to be broken down by salivary amylase. The food now referred to as the bolus is swallowed with the epiglottis, a cartilaginous flap closing over the trachea and through muscle contractions of the esophagus is then transported to the stomach. The stomach is the main site for chemical digestion of the bolus, liquefying the bolus into chyme, which is transported to the duodenum of the small intestine. It is in the duodenum of the small intestine where the bulk of nutrient absorption occurs. The cecum, though part of the digestive system, is part of the large intestine where water absorption occurs, solidifying the chyme into feces.