tunica externa

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tunica

 [too´nĭ-kah] (L.)
a tunic or coat; used in anatomic nomenclature to designate a membranous covering of an organ or a distinct layer of the wall of a hollow structure, as a blood vessel.
tunica adventi´tia the outer coat of various tubular structures.
tunica albugi´nea a dense white fibrous sheath that encloses a part or organ, such as the testicle or ovary.
tunica conjuncti´va the conjunctiva.
tunica dar´tos dartos.
tunica exter´na an outer coat, such as the fibroelastic coat of a blood vessel.
tunica inter´na an inner coat or layer.
tunica in´tima the innermost coat of a blood vessel; called also Bichat's tunic.
tunica me´dia the muscular middle coat of a blood vessel.
tunica muco´sa the mucous membrane lining of various tubular structures.
tunica muscula´ris the muscular coat or layer surrounding the tela submucosa in most portions of the digestive, respiratory, urinary, and genital tracts.
tunica pro´pria the proper coat or layer of a part, as distinguished from an investing membrane.
tunica sero´sa the membrane lining the external walls of the body cavities and reflected over the surfaces of protruding organs; it secretes a watery exudate.
tunica vagina´lis tes´tis the serous membrane covering the front and sides of the testis and epididymis.
tunica vasculo´sa a vascular coat, or a layer well supplied with blood vessels.

tu·ni·ca ex·ter·na

[TA]
1. the outer of two or more enveloping layers of any structure;
2. specifically, the outer fibroelastic coat of a blood or lymph vessel.
Synonym(s): tunica extima [TA]

tunica externa

The outermost layer of a blood vessel, which envelops the tunica media. It is composed largely of collagen and elastic lamina.

Pathology
The most commonly acquired condition that affects the tunica externa is vitamin C deficiency (scurvy), which results in defective collagen synthesis.

tu·ni·ca ex·ter·na

(tū'ni-kă eks-ter'nă) [TA]
1. The outer of two or more enveloping layers of any structure;
2. Specifically, the outer fibroelastic coat of a blood or lymph vessel.
References in periodicals archive ?
Microscopic picture would be dilated lymphatic channels with one (or) two endothelial layers with or without adventitial layer. [1]
Grant and Twigg [19] used AFM with a 10 pm tip to characterize the adventitial layer of porcine pulmonary arteries and porcine aorta.
demonstrated conclusively that, during pathological conditions, increases in the density of adventitial vasa vasorum (VV), the plexus of physiological microvessels surrounding the adventitial layer, precede endothelial dysfunction [13].
Cystic adventitial disease (CAD) is rare vascular disorder in which a mucinous cystic formation in the adventitial layer of artery disturbs the arterial blood flow and causes intermittent claudication in young-adult patient.
Two conditions (C1 and C2) were adopted from the measurements of the arterial walls, referring to the thickness of the inner plus medial layers (C1) and the thickness of the adventitial layer (C2).
Histologic examination revealed metacestodal tissue (protoscolices, inner germinal layer, intermediate thick laminated layer, and outer adventitial layer) compressing hepatic parenchyma.
Lymphatics residing in the adventitial layer of atherosclerotic vessels can drain fluid and inflammatory molecules and cells to local nodes.
Therefore, continuing along the lines these same authors followed, the partially thrombosed giant aneurysms present intramural rather than intraluminal thrombi, in addition to neovascularization of the adventitial layer and some inflammatory activity.
This zone has been identified to be loculated between the smooth muscle and the adventitial layer of the adult human vascular wall.
The wall of a cyst in the muscle is formed by three layers: the inner germina, intermediate and outer granulomatous adventitial layer. The most common skeletal sites include hip, thigh, shoulder and humerus regions.
The elastin stain demonstrates disrupted elastic fibers throughout the entire cyst wall, which indicates that the cyst emanated directly from the adventitial layer of an artery (Fig.
Diverticular wall is composed of mucosa, lamina propria, scattered thin muscle fibres and an adventitial layer. Bladder diverticula generally empty poorly during micturition, leaving a large post-void residual urine volume that results in the characteristic findings on presentation and imaging.