The mucosa of the small intestine is lined by a simple columnar epithelium which consists primarily of absorptive cells (enterocytes), with scattered goblet cells and occasional enteroendocrine cells.In crypts, the epithelium also includes Paneth cells and stem cells.he mucosa of the small intestine is characterized by evagination into plicae and villi, which increase the surface area for nutrient absorption, and by short tubular invaginations, the crypts, which provide a protected site for stem cells.
The following are sites where you can give a subcutaneous injection: 1  Abdomen: Uncover your abdomen. 2  Thigh: Uncover the entire leg. 3  Lower back: Uncover the back from the waist to the top of the buttocks.  Upper Arm: Uncover the arm to the shoulder.
1 Clean the tabletop or other area where you will have supplies for your shot. 2  Wash and dry your hands well.  Choose a place on your abdomen or your thigh for the shot. The place for the injection is called a site (see Figure 2 below for injection sites). The sites may vary depending on the medicine. Ask your doctor or nurse if you are not sure where to give the shot.