Intestinal villi (singular: villus) are tiny, finger-like structures that protrude from the wall of the intestine and have additional extensions called microvilli (singular: microvillus) which protrude from epithelial cells lining villi. They increase the absorptive area of the intestinal wall. It is important that the food is absorbed at a considerably fast rate so as to allow more food to be absorbed.(If the process is too slow, the concentration of the blood in the blood vessels and the food will be equal, thus, diffusion will not occur.)Digested nutrients (including sugars and amino acids) pass into the villi through diffusion. Circulating blood then carries these nutrients away. ^[1] Image File history File links Download high resolution version (960x678, 372 KB) Electron micrograph of nude mouse jejunum microvilli Plate 3. ... Categories: Stub ... This article or section should be merged with actin Microfilaments or actin filaments are made up of two twisted monomeric actin subunits. ... It has been suggested that this article or section be merged with Glycocalix. ... Junctional complexes (JC) are the connections between two epithelial cells. ... In zootomy, epithelium is a tissue composed of a layer of cells. ... Cell adhesion in desmosomes A desmosome (also known as macula adherens (Latin for adhering spot ) is a cell structure specialized for cell-to-cell adhesion. ... Image File history File links Gray1058. ... For other uses, see Latin (disambiguation). ... Elseviers logo. ... In anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine (or colon). ... The microvilli (singular: microvillus) are structures that increase the surface area of cells by approximately 600 fold (human), thus facilitating absorption and secretion. ... In zootomy, epithelium is a tissue composed of a layer of cells. ... This article is about sugar as food and as an important and widely-traded commodity. ... Phenylalanine is one of the standard amino acids. ...

Function

In all humans, the villi and microvilli together increase intestinal absorptive surface area 30-fold and 600-fold, respectively, providing exceptionally efficient absorption of nutrients in the lumen. This increases the surface area of the intestine to around the area of a small parking lot or a tennis court.CHAOS Link title {{portal|Food} A nutrient is either a chemical element or compound used in an organisms metabolism or physiology. ... Lumen can mean: Lumen (unit), the SI unit of luminous flux Lumen (anatomy), the cavity or channel within a tubular structure Thylakoid lumen, the inner membrane space of the chloroplast 141 Lumen, an asteroid discovered by the French astronomer Paul Henry in 1875 Lumen (band), an American post-rock band... This article does not cite any references or sources. ... This article does not cite any references or sources. ...

There are also enzymes on the surface for digestion. Villus capillaries collect amino acids and simple sugars taken up by the villi into the blood stream. Villus lacteals collect absorbed fatty acids. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... This article does not cite any references or sources. ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine. ...

Homologue of alveolus

Villi serve the same purpose as the alveoli in the lungs. Both increase surface area, which helps to increase the transfer rate of nutrients into the blood through diffusion, although alveoli also transfer wastes out. Alveoli transfer carbon dioxide out and oxygen into the bloodstream, while villi transfer digested food in. The alveoli (singular:alveolus), tiny hollow sacs which are continuous with the airways, are the sites of gas exchange with the blood. ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...

Additional images

References

1. ^ [1] Tiscali UK - Reference encyclopedia

External links

• Histology at BU 11504loa - "Digestive System: Alimentary Canal: pyloro/duodenal junction, duodenum"
• Histology at BU 11513loa - "Digestive System: Alimentary Canal: pyloro/duodenal junction"
• Histology at BU 11609loa - "Digestive System: Alimentary Canal: duodenum, plicae circularis"
• Histology at USC gi/c_36
• Histology at USC gi/c_39
• Intestinal+villi at eMedicine Dictionary