Adventitia
The outermost connective tissue covering of any organ, vessel, or other structure. For example, the connective tissue that surrounds an artery is called the adventitia because it is considered extraneous to the artery. "Adventitia" comes from the Latin "adventicius" meaning "foreign, strange, extraneous, coming from abroad or from outside." Other English words that stem from "advenire" include "adventure" and "avenue." A related term is "adventititious" meaning "coming from an external source or occurring in an unusual place or manner." When a doctor or nurse listens to the chest or abdomen, adventitious sounds are those that are normally not heard coming from the chest or abdomen.
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The outermost connective tissue covering of any organ, vessel, or other structure not covered by a serosa; instead, the covering is properly derived from without ( i.e., from the surrounding connective tissue) and does not form an integral part of such organ or structure. Terminologia Anatomica [TA] lists a. (tunica a.) of the following organs: ductus deferens, esophagus, renal pelvis, seminal glands, and ureters. SYN: membrana a. (1), tunica a.. [L. adventicius, coming from abroad, foreign, fr. ad, to + venio, to come]

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ad·ven·ti·tia .ad-vən-'tish-(ē-)ə, -(.)ven- n the outer layer that makes up a tubular organ or structure and esp. a blood vessel, is composed of collagenous and elastic fibers, and is not covered with peritoneum called also tunica adventitia, tunica externa

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n.
1. the outer coat of the wall of a vein or artery. It consists of loose connective tissue and networks of small blood vessels, which nourish the walls.
2. the outer covering of various other organs or parts.

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ad·ven·ti·tia (ad″ven-tishґe-ə) [L. adventicius foreign, from without] 1. adventitial. 2. tunica adventitia.

Medical dictionary. 2011.

Look at other dictionaries:

  • adventitia — n. 1. the membranous outer covering of an organ or blood vessel. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • Adventitia —   die, , Anatomie: äußere Bindegewebsschicht von Hohlorganen (Blutgefäße, Harnleiter u. a.) …   Universal-Lexikon

  • adventitia — [ad΄ven tish′ə, ad΄ventish′ē ə; ad΄vəntish′ə, ad΄vəntish′ē ə] n. [ModL < L, for adventicia, neut. pl. of adventicius: see ADVENTITIOUS] the outer covering of an organ, as of an artery: it is made up chiefly of connective tissue …   English World dictionary

  • Adventitia — Infobox Anatomy Name = PAGENAME Latin = GraySubject = GrayPage = Caption = Layers of Esophageal Wall: 1. Mucosa 2. Submucosa 3. Muscularis 4. Adventitia 5. Striated muscle 6. Striated and smooth 7. Smooth muscle 8. Lamina muscularis mucosae 9.… …   Wikipedia

  • Adventitia — Als Tunica adventitia oder Adventitia (von lat. advenire hinzukommen) wird in der Anatomie die äußere Schicht um schlauchförmige Organe bezeichnet. Die Adventitia besteht aus lockerem Bindegewebe und dient der Verankerung in der Umgebung. In der… …   Deutsch Wikipedia

  • adventitia — noun The outermost layer of epithelial tissue encasing a visceral organ. See Also: adventitia bona, adventitious, tunica adventitia …   Wiktionary

  • Adventitia — Ad|venti̱tia w; , ...ti̱tiae: übliche Kurzbez. für ↑Tunica adventitia …   Das Wörterbuch medizinischer Fachausdrücke

  • Adventitia — Ad|ven|ti|tia die; , ...tiae [...ti̯ɛ] <aus gleichbed. nlat. (tunica) adventitia zu lat. adventicius »(von außen) hinzukommend; äußerer«> die aus Bindegewebe u. elastischen Fasern bestehende äußere Wand der Blutgefäße (Med., Biol.) …   Das große Fremdwörterbuch

  • adventitia — [ˌadvɛn tɪʃə] noun the outermost layer of the wall of a blood vessel. Derivatives adventitial adjective Origin C19: shortening of mod. L. tunica adventitia additional sheath …   English new terms dictionary

  • adventitia — tunica adventitia; n. 1) the outer coat of the wall of a vein or artery. It consists of loose connective tissue and networks of small blood vessels, which nourish the walls. 2) the outer covering of various other organs or parts …   The new mediacal dictionary

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