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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. Each of these microvilli are about 1 ...
Goblet cells secrete mucus, which lubricates the passage of food along and protects the intestinal wall from digestive enzymes. In the small intestine, villi are folds of the mucosa that increase the surface area of the intestine.
Subsets of sensory intestinal epithelial cells synapse with nerves, [9] and are known as neuropod cells. [10] Paneth cells produce antimicrobial peptides such as human alpha-defensin. [11] [12] Microfold cells (commonly referred to as M cells) sample antigens from the lumen and deliver them to the lymphoid tissue associated with the mucosa (MALT).
The villi of the jejunum look like long, finger-like projections, and are a histologically identifiable structure. While the length of the entire intestinal tract contains lymphoid tissue , only the ileum has abundant Peyer's patches , which are unencapsulated lymphoid nodules that contain large numbers of lymphocytes and immune cells, like ...
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.
During each mitosis, one of the two daughter cells remains in the crypt as a stem cell, while the other differentiates and migrates up the side of the crypt and eventually into the villus. These stem cells can differentiate into either an absorptive (enterocytes) or secretory (Goblet cells, Paneth cells, enteroendocrine cells) lineages. [3]
Smooth muscle fibers may be in the lamina propria, such as in the intestinal villi. It is practically void of fat cells. [4] Lymphatics penetrate the mucosa and lie below the basement membrane of the epithelium, from there they drain the lamina propria. [8] The fast rate of cell death and regeneration of the epithelium leaves behind many ...
Simple columnar epithelium is a single layer of columnar epithelial cells which are tall and slender with oval-shaped nuclei located in the basal region, attached to the basement membrane. In humans, simple columnar epithelium lines most organs of the digestive tract including the stomach , and intestines .