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.
Intramuscular (IM) injections deposit medication deeply into vascular muscle tissue, thus allowing rapid absorption. The deltoid, vastus lateralis, and ventrogluteal muscles are acceptable sites for IM injections. Previously, the dorsogluteal site was widely accepted and used, but current evidence has demonstrated that it is not acceptable due to its high risk for injury. When preparing to give an IM injection, examine the site to determine that there is adequate muscle tissue. Avoid any areas with lesions, trauma, inflammation, or bony prominences. To prevent tissue damage, rotate IM injection sites when injections are regularly scheduled.