Connective tissue
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Reverted edits by [[Special:Contributions/195.224.166.158|195.224.166.158]] ([[User talk:195.224.166.158|talk]]) to last version by Excirial
'''Connective tissue''' is one of the four types of [[biological tissue|tissue]] in traditional classifications (the others being [[epithelium|epithelial]], [[muscle]], and [[nervous tissue]]). It is largely a category of exclusion rather than one with a precise definition, but all or most tissues in this category are similarly:
* Involved in structure and support.
* Derived from [[mesoderm]], usually.
* Characterized largely by the traits of non-living tissue.
[[Blood]], [[cartilage]], and [[bone]] are usually considered connective tissue, but because they differ so substantially from the other tissues in this class, the phrase "connective tissue proper" is commonly used to exclude those three. There is also variation in the classification of embryonic connective tissues; on this page they will be treated as a third and separate category.
[[Collagen]] is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% of the total protein content.<ref>{{cite journal |url=http://www.jbc.org/cgi/content/abstract/277/6/4223|year=2002|author=Di Lullo, G. A.|title=Mapping the Ligand-binding Sites and Disease-associated Mutations on the Most Abundant Protein in the Human, Type I Collagen|journal=Journal of Biological Chemistry|volume=||pmid=11704682|doi=10.1074/jbc.M110709200|pages=4223}}</ref>
==Classification==
The old classification system for connective tissue is proper versus specilized. There has been a new classifications system proposed, however, and it is as follows:
Loose connective tissue
* Areolar
* Adipose
* Reticular
[[Dense connective tissue]]
* Regular
* Irregular
* Elastic
Cartilage
* Hyaline
* Fibrocartilage
* Elastic
Other
* Bone
* Blood
* Lymphatics
===Connective tissue proper===
[[Image:Illu connective tissues 1.jpg|thumb|500px|Connective tissue proper]]
* [[Areolar connective tissue|Areolar (or loose) connective tissue]] holds organs and epithelia in place, and has a variety of [[protein]]aceous fibres, including collagen and [[elastin]].
* [[Fibrous connective tissue]] forms [[ligament]]s and [[tendon]]s. Its densely packed collagen fibers have great tensile strength.
===Specialized connective tissues===
[[Image:Illu connective tissues 2.jpg|thumb|600px|Specialized connective tissues]]
* [[Blood]] functions in transport. Its extracellular matrix is [[blood plasma]], which transports dissolved [[nutrient]]s, [[hormone]]s, and [[carbon dioxide]] in the form of [[bicarbonate]]. The main cellular component is [[red blood cell]]s.
* [[Bone]] makes up virtually the entire skeleton in adult vertebrates.
* [[Cartilage]] makes up virtually the entire skeleton in [[chondrichthyes]]. In most other [[vertebrate]]s, it is found primarily in [[joint]]s, where it provides cushioning. The extracellular matrix of cartilage is composed primarily of [[collagen]].
* [[Adipose tissue]] contains [[adipocyte]]s, used for [[cushioning]], [[thermal insulation]], [[lubrication]] (primarily in the [[pericardium]]) and [[energy]] storage.
* [[Reticular connective tissue]] is a network of reticular fibres (fine collagen, type III) that form a soft skeleton to support the [[lymphoid]] organs ([[lymph nodes]], [[bone marrow]], and [[spleen]].)
===Embryonic connective tissues===
* [[Mesenchyme|Mesenchymal connective tissue]]
* [[Mucous connective tissue]]
==Fiber types==
Fiber types as follows:
* [[collagenous fibers]]
* [[elastic fibers]]
* [[reticular fibers]]
== Disorders of connective tissue ==
Various connective tissue conditions have been identified; these can be both inherited and environmental.
* [[Marfan syndrome]] - a genetic disease causing abnormal [[fibrillin]].
* [[Scurvy]] - caused by a dietary deficiency in [[vitamin C]], leading to abnormal [[collagen]].
* [[Ehlers-Danlos syndrome]] - deficient type III collagen- a genetic disease causing progressive deterioration of collagens, with different EDS types affecting different sites in the body, such as joints, heart valves, organ walls, arterial walls, etc.
* [[Loeys-Dietz syndrome]] - a genetic disease related to Marfan syndrome, with an emphasis on vascular deterioration.
* [[Pseudoxanthoma elasticum]] - an autosomal recessive hereditary disease, caused by calcification and fragmentation of elastic fibres, affecting the skin, the eyes and the cardiovascular system.
* [[Systemic lupus erythematosus]] - a chronic, multisystem, inflammatory disorder of probable autoimmune etiology, occurring predominantly in young women.
* [[Osteogenesis imperfecta]] (brittle bone disease) - caused by insufficient production of good quality collagen to produce healthy, strong bones.
* [[Fibrodysplasia ossificans progressiva]] - disease of the connective tissue, caused by a defective gene which turns connective tissue into [[bone]].
* Spontaneous [[pneumothorax]] - collapsed lung, believed to be related to subtle abnormalities in connective tissue.
* [[Sarcoma]] - a [[neoplastic]] process originating within connective tissue.
==Staining of connective tissue==
For microscopic viewing, the majority of the connective tissue staining techniques color tissue fibers in contrasting shades. Collagen may be differentially stained by any of the following techniques:
*[[Van Gieson's]] stain
*[[Masson's trichrome|Masson's Trichrome]] stain
*[[Mallory's Aniline Blue]] stain
*[[Azocarmine]] stain
*[[Krajian's Aniline Blue]] stain
==References==
{{reflist}}
==External links==
* {{eMedicineDictionary|connective+tissue}}
* {{Dorlands|t_12|12810256}}
* [http://www.britannica.com/eb/article-9110162/connective-tissue Encyclopaedia Britannica, Connective Tissue]
* [http://www.kumc.edu/instruction/medicine/anatomy/histoweb/ct/ct.htm Overview at kumc.edu]
* {{UIUCHistologySubject|230}}
* [http://www.medicine.uiowa.edu/anatomy/dental/genhisto/GHWIN/unit3/index.html Connective tissue atlas at uiowa.edu]
{{Biological tissue}}
{{Connective tissue}}
[[Category:Tissues]]
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[[es:Tejido conjuntivo]]
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[[nl:Bindweefsel]]
[[ja:結合組織]]
[[no:Støttevev]]
[[nn:Bindevev]]
[[om:Connective tissue]]
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[[ru:Соединительная ткань]]
[[sr:Везивно ткиво]]
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[[th:เนื้อเยื่อเกี่ยวพัน]]
[[vi:Mô liên kết]]
[[tr:Bağ doku]]
[[uk:Сполучна тканина]]
[[zh:结缔组织]]