View source for Lacteal

{{Infobox Anatomy |
  Name         = Lacteal |
  Latin        = |
  GraySubject  = |
  GrayPage     = |
  Image        = Gray1060.png |
  Caption      = Transverse section of a [[villus]], from the human [[intestine]]. X 350.<BR>a. [[Basement membrane]], here somewhat shrunken away from the epithelium.<BR>b. Lacteal.<BR>c. [[Columnar epithelium]].<BR>d. Its striated border.<BR>e. [[Goblet cells]].<BR>f. [[Leucocytes]] in epithelium.<BR>f’. Leucocytes below epithelium.<BR>g. [[Bloodvessels]].<BR>h. [[Muscle cells]] cut across. |
  Image2       = Gray1061.png |
  Caption2     = Villi of small intestine, showing bloodvessels and lymphatic vessels. |
  System       = |
  MeshName     = |
  MeshNumber   = |
  DorlandsPre  = l_01 |
  DorlandsSuf  = 12474659  |
}}
A '''lacteal''' is a [[lymphatic|lymphatic capillary]] that absorbs dietary [[Fat|fats]] in the [[Intestinal villus|villi]] of the [[small intestine]]. 

The combination of fat and lymph in the lacteals is milky in appearance and called [[chyle]]. Individual lacteals merge to form larger lymphatic vessels that transport the fats to the [[thoracic duct]] which empties into the left [[subclavian vein]] found under the collar bone.

At this point, the fats are in the bloodstream in the form of [[chylomicrons]]. Once in the blood, chylomicrons are subject to delipidation by lipoprotein lipase. Eventually, enough lipid has been lost and additional [[apolipoprotein|apolipoproteins]] gained, that the resulting particle (now referred to as a chylomicron remnant) can be taken up by the liver. From the liver, the fat released from chylomicron remnants can be re-exported to the blood as the triglyceride component of [[VLDL|very low density lipoprotein (VLDL)]]. VLDL, also subject to delipidation by vascular lipoprotein lipase, delivers fats to tissues throughout the body and, in particular, the released fatty acids can be stored in [[adipose]] cells as [[triglycerides]]. As triglycerides are lost from VLDL the lipoprotein particle becomes smaller and denser (since protein is denser than lipid) and ultimately becomes [[LDL|low density lipoprotein (LDL)]]. A lot has been written about LDL because it is thought to be [[Atherogenesis|atherogenic]].

Note that in contrast to any other route of absorption from the small intestine, the lymphatic system avoids first pass metabolism.
==See also==
* [[Villus]]

==External links==
* {{eMedicineDictionary|lacteal}}
* {{BUHistology|11705loa}} - "117. Digestive System: Alimentary Canal  jejunum, central lacteals "
* [http://www.mansfield.ohio-state.edu/~jbradley/LactealA.html Diagram at ohio-state.edu]

[[Category:Digestive system]]
[[Category:Lymphatic system]]


{{digestive-stub}}

[[ja:乳糜管]]
[[Category:2Fix]]