The tunica externa (New Latin "outer coat"), also known as the tunica adventitia (New Latin "additional coat"),[1][2] is the outermost tunica (layer) of a blood vessel, surrounding the tunica media. It is mainly composed of collagen and, in arteries, is supported by external elastic lamina. The collagen serves to anchor the blood vessel to nearby organs, giving it stability.
The tunica externa provides basic structural support to blood vessels.[1] It prevents vessels from expanding too much from internal blood pressure, particularly arteries.[2] It is also relevant in controlling vascular flow in the lungs.[1]
Clinical significance
A common pathological disorder concerning the tunica externa is scurvy, also known as vitamin 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 rupture, leading to a multitude of problems.
This article incorporates text in the public domain from page 499 of the 20th edition ofGray's Anatomy(1918)
^ abcdeHunt, J. M.; Graham, B. B. (2014-01-01), McManus, Linda M.; Mitchell, Richard N. (eds.), "Pulmonary Hypertension/Pulmonary Arterial Hypertension", Pathobiology of Human Disease, San Diego: Academic Press, pp. 2625–2635, doi:10.1016/b978-0-12-386456-7.05306-5, ISBN978-0-12-386457-4, retrieved 2020-12-29
^ abcMaleszewski, J. J.; Lai, C. K.; Veinot, J. P. (2016-01-01), Buja, L. Maximilian; Butany, Jagdish (eds.), "Chapter 1 - Anatomic Considerations and Examination of Cardiovascular Specimens (Excluding Devices)", Cardiovascular Pathology (Fourth Edition), San Diego: Academic Press, pp. 1–56, doi:10.1016/b978-0-12-420219-1.00001-x, ISBN978-0-12-420219-1, retrieved 2020-12-29
External links
- Comparative Organology at University of California, Davis - "Bird, vessels (LM, High)"
tunica, externa, tunica, externa, latin, outer, coat, also, known, tunica, adventitia, latin, additional, coat, outermost, tunica, layer, blood, vessel, surrounding, tunica, media, mainly, composed, collagen, arteries, supported, external, elastic, lamina, col. The tunica externa New Latin outer coat also known as the tunica adventitia New Latin additional coat 1 2 is the outermost tunica layer of a blood vessel surrounding the tunica media It is mainly composed of collagen and in arteries is supported by external elastic lamina The collagen serves to anchor the blood vessel to nearby organs giving it stability Tunica externaSection of a medium sized artery DetailsPart ofWall of blood vesselsIdentifiersLatinTunica externa tunica adventitiaTA98A12 0 00 017TA23920THH3 09 02 0 01009Anatomical terminology edit on Wikidata The three layers of the blood vessels are an inner tunica intima a middle tunica media and an outer tunica externa Contents 1 Structure 2 Function 3 Clinical significance 4 Additional images 5 See also 6 References 7 External linksStructure EditThe tunica externa is made from collagen and elastic fibers in a loose connective tissue 1 2 This is secreted by fibroblasts 1 Function EditThe tunica externa provides basic structural support to blood vessels 1 It prevents vessels from expanding too much from internal blood pressure particularly arteries 2 It is also relevant in controlling vascular flow in the lungs 1 Clinical significance EditA common pathological disorder concerning the tunica externa is scurvy also known as vitamin 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 rupture leading to a multitude of problems Additional images Edit Transverse section through a small artery and vein of the mucous membrane of the epiglottis of a child Tunica adventitia is at a Microphotography of arterial wall with calcified violet colour atherosclerotic plaque haematoxylin amp eosin stain See also EditAdventitiaReferences Edit This article incorporates text in the public domain from page 499 of the 20th edition of Gray s Anatomy 1918 a b c d e Hunt J M Graham B B 2014 01 01 McManus Linda M Mitchell Richard N eds Pulmonary Hypertension Pulmonary Arterial Hypertension Pathobiology of Human Disease San Diego Academic Press pp 2625 2635 doi 10 1016 b978 0 12 386456 7 05306 5 ISBN 978 0 12 386457 4 retrieved 2020 12 29 a b c Maleszewski J J Lai C K Veinot J P 2016 01 01 Buja L Maximilian Butany Jagdish eds Chapter 1 Anatomic Considerations and Examination of Cardiovascular Specimens Excluding Devices Cardiovascular Pathology Fourth Edition San Diego Academic Press pp 1 56 doi 10 1016 b978 0 12 420219 1 00001 x ISBN 978 0 12 420219 1 retrieved 2020 12 29External links EditAnatomy photo Circulatory vessels vessels7 vessels4 Comparative Organology at University of California Davis Bird vessels LM High Portal Anatomy Retrieved from https en wikipedia org w index php title Tunica externa amp oldid 1083810587, wikipedia, wiki, book, books, library,
