https://www.wikidoc.org/index.php?title=Enterocyte&feed=atom&action=history
Enterocyte - Revision history
2024-03-28T18:38:14Z
Revision history for this page on the wiki
MediaWiki 1.40.0
https://www.wikidoc.org/index.php?title=Enterocyte&diff=673617&oldid=prev
WikiBot: Bot: Automated text replacement (-{{SIB}} + & -{{EJ}} + & -{{EH}} + & -{{Editor Join}} + & -{{Editor Help}} +)
2012-08-09T02:16:40Z
<p>Bot: Automated text replacement (-{{SIB}} + & -{{EJ}} + & -{{EH}} + & -{{Editor Join}} + & -{{Editor Help}} +)</p>
<p><b>New page</b></p><div>{{CMG}}<br />
<br />
<br />
<br />
==Overview==<br />
{{SI}}<br />
'''Enterocytes''', or '''intestinal absorptive cells''', are [[simple columnar]] [[epithelial cells]] found in the [[small intestines]] and [[colon]]. A [[glycocalyx]] surface coat contains digestive enzymes. [[Microvilli]] on the apical surface increase surface area for the digestion and transport of molecules from the intestinal lumen. The cells also have a secretory role.<br />
<br />
==Functions==<br />
[[Image:Alpha Intercalated Cell Cartoon.jpg|thumb|left|250px|[[Apical membrane]] and [[Basolateral membrane]] ]]The major functions of enterocytes include<ref> Ross, M.H. & Pawlina, W. 2003. ''Histology: A Text and Atlas, 4th Edition.'' Lippincott Williams & Wilkins, Philadelphia.</ref>:<br />
*'''Ion uptake''', including sodium, calcium, magnesium, and iron. This typically occurs through [[active transport]]. <br />
*'''Water uptake'''. This follows the osmotic gradient established by [[NaKATPase|Na+/K+ ATPase]] on the basolateral surface. This can occur [[diffusion|transcellularly]] or [[paracellular transport|paracellularly]]. <br />
*'''Sugar uptake'''. Polysaccharidases and disaccharidases in the glycocalyx break down large sugar molecules, which are then absorbed. [[Glucose]] crosses the [[apical membrane]] of the enterocyte using the Na<sup>+</sup> dependent [[glucose transporter]]. It moves through the [[cytosol]] (cytoplasm) and exits the enterocyte via the [[basolateral membrane]] (into the [[blood capillary]]) using GLUT-2 ({{Gene|SLC2A2}}). [[Galactose]] uses the same transport system. [[Fructose]], on the other hand, crosses the apical membrane of the enterocyte, using GLUT-5 ({{Gene|SLC2A5}}). It is thought to cross into the blood capillary using one of the other GLUT transporters.<br />
*'''Peptide and amino acid uptake'''. Peptidases in the glycocalyx cleave proteins to amino acids or small peptides. [[Enteropeptidase]] is responsible for activating [[pancreatic]] [[trypsinogen]] into [[trypsin]], which activates other pancreatic [[zymogens]]. <br />
*'''Lipid uptake'''. Lipids are broken down by [[pancreatic]] [[lipase]] and [[bile]], and then diffuse into the enterocytes. Smaller lipids are transported into intestinal capillaries, while larger lipids are processed by the [[Golgi]] and [[smooth endoplasmic reticulum]] into lipoprotein [[chylomicra]] and [[exocytosis|exocytozed]] into [[lacteals]]. <br />
*'''Vitamin uptake'''. Receptors bind to the [[vitamin B12|vitamin B{{ssub|12}}]]-[[intrinsic factor|gastric intrinsic factor]] complex and are taken into the cell. <br />
*'''Resorption of unconjugated bile salts'''. Bile that was released and not used in emulsification of lipids are reabsorbed in the [[ileum]]. Also known as the [[enterohepatic circulation]].<br />
*'''Secretion of immunoglobulins'''. [[Immunoglobulin A|IgA]] from [[plasma cells]] in the [[mucosa]] are absorbed through receptor mediated [[endocytosis]] on the basolateral surface and released as a receptor-IgA complex into the intestinal lumen. The receptor component confers additional stability to the molecule.<br />
<br />
==Pathology==<br />
[[Fructose malabsorption|Dietary fructose intolerance]] occurs when there is a deficiency in the amount of [[fructose carrier]]. <br />
<br />
[[Lactose intolerance]] is the most common problem of carbohydrate digestion and is created by an insufficient amount of [[lactase]] (a disaccharidase) enzyme, which is used to break down the sugar. As a result of this deficiency, undigested lactose cannot be absorbed and is instead passed on to the colonic bacteria, which metabolize the lactose. The bacteria release gas and metabolic products that enhance colonic motility. <br />
<br />
Problems with the gastric intrinsic factor or its receptor can result in [[pernicious anemia]].<br />
<br />
==References==<br />
{{Reflist}} <br />
<br />
==External links==<br />
* {{BUHistology|11706loa}} - "Digestive System: Alimentary Canal - jejunum, goblet cells and enterocytes"<br />
* {{MeshName|Enterocytes}}<br />
<br />
[[Category:Cells]]<br />
<br />
<br />
{{Gastrointestinal physiology}}<br />
[[de:Enterozyt]]<br />
[[fr:Entérocyte]]<br />
[[pl:Enterocyt]]<br />
[[pt:Enterócito]]<br />
<br />
{{WH}}<br />
{{WS}}</div>
WikiBot