Il. PARTS OF THE DIGESTIVE TRACT A. ORAL CAVITY After ingestion, the physical breakdown of solid foods (mechanical digestion) begins in the oral cavity (mouth). Describe how food is mechanically digested in the oral cavity. Include a discussion of how the teeth, tongue, and saliva work together to convert solid food into a moist, semi-solid mass of food called a bolus. Example: think of how a hard, dry saltine cracker is converted into a moist ball (bolus) in the mouth B. PHARYNX and ESOPHAGUS 1. After food has been mechanically digested, mixed with saliva, and a bolus has formed, it is swallowed. Swallowing moves the bolus from the mouth into the esophagus. Discuss the events that occur during swallowing 2. Which portions of the pharynx does food pass through when swallowing? 3. After swallowing, the bolus of food enters the esophagus. Describe the structure ocation, and function of the esophagus