Intestinal villus

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Intestinal villi (singular: villus ) is a small finger-like projection that extends into the lumen of the small intestine. Each villus has a length of about 0.5-1.6 mm (in humans), and has many microvillas projected from its epithelial enterocytes that collectively form lurik or border brushes. Each microvilli is much smaller than one villus. The intestinal vili is much smaller than the circular fold in the intestine.

Villi increase the internal surface area of ​​the intestinal wall so that a larger surface area for absorption is available. Increased absorption areas are useful because the digested nutrients (including monosaccharides and amino acids) enter semipermeable villi through diffusion, which is effective only at short distances. In other words, the increase in surface area (contact with the fluids in the lumen) reduces the average distance traveled by the nutrient molecule, so that the effectiveness of the diffusion increases. The vili connect to the blood vessels so that the circulating blood then carries these nutrients away.

Video Intestinal villus

Struktur

Histologi

Enterocytes, together with goblet cells, represent major cell types of villous epithelium in the small intestine.

Maps Intestinal villus

Function

There, villi and microvilli increased the surface area of ​​bowel absorption by about 30-fold and 600-fold, respectively, providing highly efficient nutrient absorption in the lumen.

There is also an enzyme (digestive enzyme enterocyte) on the surface for digestion. The villus capillaries collect amino acids and simple sugars taken by the villi into the bloodstream. Villus lacteal (capillary lymph) collects serotonin, which is a lipoprotein that consists of triglycerides, cholesterol and amphipathic proteins, and is carried throughout the body through lymph fluids.

Villi specifically for absorption in the small intestine because they have thin walls, one thick cell, which allows shorter diffusion pathways. They have a large surface area so that there will be more efficient absorption of fatty acids and glycerol into the bloodstream. They have a rich blood supply to maintain gradient concentrations.

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Additional images

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References

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Further reading

• C.W. Chan, Y.K. Leung and K.W. Chan (2014). "The microscopic anatomy of the vasculature of the human intestinal villi - a study with reviews". Eur J Anat , 18 (4): 291-301.

Source of the article : Wikipedia