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.
For regularly scheduled SubQ injections, rotate injection sites both within each location as well as among sites. Doing so prevents tissue damage from repeated injections at the same site. Do not administer more than 1 mL with a single SubQ injection. Use a 25- to 30-gauge, â- to â-inch needle. Determine the length of needle and the angle of injection from the patientâs body weight and the amount of subcutaneous tissue present.