from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The membranous outer covering of an organ or a blood vessel.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The outermost layer of epithelial tissue encasing a visceral organ.

from the GNU version of the Collaborative International Dictionary of English

  • n. the membranous outer covering of an organ or blood vessel.

from The Century Dictionary and Cyclopedia

  • n. In anatomy, any membranous structure covering an organ but not properly belonging to it (in full, membrana adventitia, adventitious membrane); specifically, the outermost of the three coats of a blood-vessel (in full, tunica adventitia, adventitious tunic), consisting of connective tissue.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. an enveloping or covering membrane or layer of body tissue


New Latin, from Latin adventīcius, foreign; see adventitious.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From the Latin adventitius ("extraneous"). (Wiktionary)


  • Outer layer: The outer layer the adventitia shields the artery from the rest of your body like sausage casing; it holds the artery together from the outside.

    You: On a Diet

  • Figure 5.2 Moving Through The artery has three layers—the inner to help blood move through the artery (intima), the outer (adventitia) to protect it from the outside, plus a middle, muscular layer (media).

    You: On a Diet

  • The histological examination showed a large increase of the connective tissue of the adventitia and of the connective tissue of the intima, but the muscular fibres were normal.

    Alexis Carrel - Nobel Lecture

  • This thickening was mainly produced by an augmentation of the connective tissue of the adventitia and of the intima.

    Alexis Carrel - Nobel Lecture

  • This network forms an adventitia to the bloodvessels.

    XI. Splanchnology. 4c. The Thymus

  • This latter is composed of a few circular unstriped muscle cells a. The adventitia, similar in structure to that of an artery.

    Illustrations. Fig. 448

  • The adventitia gradually merges into the surrounding connective tissue.

    Illustrations. Fig. 448

  • The fibrous coat (tunica adventitia) is continuous at one end with the fibrous tunic of the kidney on the floor of the sinus; while at the other it is lost in the fibrous structure of the bladder.

    XI. Splanchnology. 3b. 2. The Ureters

  • —The arteries are composed of three coats: an internal or endothelial coat (tunica intima of Kölliker); a middle or muscular coat (tunica media); and an external or connective-tissue coat (tunica adventitia).

    V. Angiology. Introduction

  • The endothelium is supported on a membrane separable into two layers, the outer of which is the thicker, and consists of a delicate, nucleated membrane (adventitia), while the inner is composed of a network of longitudinal elastic fibers (media).

    V. Angiology. Introduction


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