A drug intended to increase epithelial turnover in the small intestine would target which structure?

• A. Goblet cells
• B. Mature enterocytes
• C. Folds of Kerckring
• D. Crypt cells

Answer: (D)

The renewal of the intestinal epithelium is driven by stem cells located in the crypts of Lieberkühn at the base of the villi. These crypt cells include stem cells and rapidly dividing progenitors that continually generate new enterocytes and secretory cells, pushing them upward to replace older cells as they are shed at the villus tip. A drug that increases epithelial turnover would act on this proliferative compartment to boost renewal. In contrast, mature enterocytes and goblet cells are already differentiated and migrate up the villus; folds of Kerckring are anatomical structures that increase surface area and are not themselves sites of continual cell proliferation. Therefore, the target would be the crypt cells.