Search results
Results from the WOW.Com Content Network
Intestinal glands are found in the epithelia of the small intestine, namely the duodenum, jejunum, and ileum, and in the large intestine (colon), where they are sometimes called colonic crypts. Intestinal glands of the small intestine contain a base of replicating stem cells, Paneth cells of the innate immune system, and goblet cells, which ...
Paneth cells are found throughout the small intestine and the appendix at the base of the intestinal glands. [2] There is an increase in Paneth cell numbers towards the end of the small intestine. [3] Like the other epithelial cell lineages in the small intestine, Paneth cells originate at the stem cell region near the bottom of the gland. [4]
Micrograph of the small intestine mucosa showing the intestinal villi and crypts of Lieberkühn. The three sections of the small intestine look similar to each other at a microscopic level, but there are some important differences. The parts of the intestine are as follows: This cross section diagram shows the 4 layers of the small intestine wall.
The barrier formed by the intestinal epithelium separates the external environment (the contents of the intestinal lumen) from the body [15] and is the most extensive and important mucosal surface of body. [18] The intestinal epithelium serves several crucial functions, exhibiting both innate and adaptive immune features.
Intestinal villi (sg.: villus) are small, finger-like projections that extend into the lumen of the small intestine. Each villus is approximately 0.5–1.6 mm in length (in humans), and has many microvilli projecting from the enterocytes of its epithelium which collectively form the striated or brush border .
Diagram showing the location of intestinal crypts and the gradual migration of differentiating cells out of the crypt. Similar to gastric basal cells, intestinal basal cells are continuously propagating.
In the large intestines, villi are absent and a flat surface with thousands of glands is observed. Underlying the epithelium is the lamina propria, which contains myofibroblasts, blood vessels, nerves, and several different immune cells, and the muscularis mucosa which is a layer of smooth muscle that aids in the action of continued peristalsis ...
In the adult intestine, the crypts of Lieberkühn are the niche for epithelial stem cells and contain all proliferative stem and progenitor cells. Differentiating cells exit the cell cycle and migrate out of the crypts and onto the surface epithelium of the intestine, where they perform their physiological role (e.g., nutrient absorption by enterocytes; mucous secretion by goblet cells) and ...