BIOS 256 Week 1 Quiz. I n t r o d u c t i o n 1. Define the gastrointestinal tract (GI). A continues tube from the mouth to the anus. 2. Identify three mechanical digestion activities. a. chewing (mastification), turning food into bolus b. with help of mixing food with saliva c. churning of the food in the stomach and segmentation of the intestines 3. Name two feedback loops that regulate digestive system smooth muscle responsible for propulsive and mixing movements. Hormonal feedback lo...