Link to: 23.1 The GI tract 9. This layer of the GI tract is composed of areolar connective tissue that binds the mucosa to the muscularis. A) Submucosa B) Lamina propria C) Epithelium D) Serosa E) None of the above Ans: A Link to: 23.1 The GI tract 10. This layer functions by secreting a lubricating fluid. A) Serosa B) Submucosa C) Muscularis D) Mucosa E) MALT Ans: A Link to: 23.6 In the small intestine 11. These are composed of prominent lymphatic nodules that function in the immune response.