- Tunica externa (vessels)
Infobox Anatomy
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Latin = tunica externa vasorum, tunica adventitia vasorum
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GrayPage = 499
Caption = Section of a medium-sizedartery .
Caption2 = Transverse section through a smallartery andvein of themucous membrane of theepiglottis of a child. (Tunica adventitia is at 'a')
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DorlandsPre = t_22
DorlandsSuf = 12831733
The tunica externa, also known as the tunica adventitia, is the outermost layer of ablood vessel , surrounding thetunica media . It is mainly composed ofcollagen . The collagen serves to anchor the blood vessel to nearby organs, giving it stability.Pathology
A common pathological disorder concerning the "tunica externa" is
scurvy , also known asvitamin C deficiency. Scurvy occurs because vitamin C is essential for the synthesis of collagen, and without it, the faulty collagen cannot maintain the vein walls, and they rupture, leading to a wide multitude of problems.
=Additionalee also
*
Adventitia
*Tunica media
*Tunica intima External links
* - "Bird, vessels (LM, High)"
*
* [http://biology.about.com/library/organs/heart/bltunica3.htm Image at About.com]
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