It has been well established that vertebrates of lower species, particularly urodele amphibians (common called “salamanders”), have an intrinsic capacity to regenerate a variety of body parts, including limbs, tail, jaw, and retina.
In higher mammals, examples of complex tissue regeneration are less common but can be seen in the seasonal regrowth of deer antlers.
In the human body the gastrointestinal (GI) tract is lined with mucosal tissues or mucosa.
As shown in Figure 7.0.1, mucosa is primarily comprised of epithelial cells that are attached to the basement membrane. Protruding from the wall of the intestine are tiny, finger-like projections called villi that increase the absorptive area and the surface area of the intestinal wall.