Your lesson sounds like a fun and interactive activity that students will be able to remember easily because it involves the students to be creative to re-create the digestive system. It is similar to the activity that was in a recent workshop I was involved that was teaching about bones, muscles, and joints. As a culminating activity, students were given a baggie of miscellaneous items and were assigned to create a part of the body that represented bones muscles and joints. Some of the items available to use were: cotton balls, tooth picks, small dole rods, rubber bands, twist ties, paper clips, and straws. It was interesting to see the variety of outcomes they built, but it was apparent that they had a good understanding of how bones, muscles, and joints work together.