Intestinal villi 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, 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 µm in length, around 1000 times shorter than a single villus. The intestinal villi are much smaller than any of the circular folds in the intestine.
Micrograph of the small intestine mucosa showing villi – top half of image. H&E stain
Cross-section histology of small intestinal villi of the human terminal ileum.
MicroCT-based volume projection of the jejunal mucosa of a chicken. Virtual volume block with vertically truncated villi in oblique view. Scalebar = 0.2 mm.
MicroCT-based volume projection of the jejunal mucosa of a chicken. Virtual horizontal cut through villi. Scalebar = 0.2 mm.
Microvilli are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction.
Enterocytes with microvilli
