tunica media

Examples of tunica media in the following topics:

• Elastic Arteries

  • An elastic or conducting artery has a large number of collagen and elastin filaments in the tunica media.
  • Elastic arteries contain larger numbers of collagen and elastin filaments in their tunica media than muscular arteries do, giving them the ability to stretch in response to each pulse.
  • Due to position as the first part of the systemic circulatory system closest to the heart and the resultant high pressures it will experience, the aorta is perhaps the most elastic artery, featuring an incredibly thick tunica media rich in elastic filaments.
  • Arterial wall layers including the tunica intima and the tunica media.
  • In elastic arteries, the tunica media is rich with elastic and connective tissue.

• Artery Function

  • As with veins, arteries are comprised of three layers: the tunicae intima, media, and externa.
  • In arteries, the tunica media, which contains smooth muscle cells and elastic tissue, is thicker than that of veins so it can modulate vessel caliber and thus control and maintain blood pressure.
  • Arteries of the systemic circulation can be subdivided into muscular or elastic types according to the the relative compositions of elastic and muscle tissue in their tunica media.

• Blood Vessel Structure

  • The tunica intima is surrounded by a thin membrane comprised of elastic fibers running parallel to the vessel.
  • Surrounding the tunica intima is the tunica media, comprised of smooth muscle cells and elastic and connective tissues arranged circularly around the vessel.
  • The outermost layer is the tunica externa or tunica adventitia, composed entirely of connective fibers and surrounded by an external elastic lamina which functions to anchor vessels with surrounding tissues.
  • The tunica externa is often thicker in veins to prevent collapse of the blood vessel and provide protection from damage since veins may be superficially located.
  • This diagram of the artery wall indicates the smooth muscle, external elastic membrane, endothelium, internal elastic membrane, tunica externa, tunica media, and tunica intima.

• Blood Flow in the Skin

  • The skin contains a network of small blood vessels containing muscle fibers in their tunica media.

• Role of the Cardiovascular Center

  • The vasomotor centres control vessel tone or contraction of the smooth muscle in the tunica media.

• Arteries, Veins, and Capillaries

  • The inner, tunica intima is a smooth, inner lining of endothelial cells that are in contact with the red blood cells.
  • Veins and arteries both have two further tunics that surround the endothelium: the middle, tunica media is composed of smooth muscle, while the outer tunica externa is connective tissue (collagen and elastic fibers).
  • Arteries and veins consist of three layers: an outer tunica externa, a middle tunica media, and an inner tunica intima.
  • Capillaries consist of a single layer of epithelial cells, the endothelium tunic (tunica intima).

• Local Regulation of Blood Flow

  • Arterioles contain smooth muscle fibers in their tunica media which allows for fine control of their diameter.

• Muscular Arteries

  • Muscular arteries can be identified by the well-defined elastic lamina that lies between the tunicae intima and media.

• Coronary Artery Disease

  • Characteristics of atherosclerosis shown here include thickening of the tunica intima, fragmentation of the internal elastic lamina (a very thin black wavy layer) between the intima and media, partial duplication of the internal elastic lamina, smooth muscle infiltration of the intima (from the media, red staining of the intima), and luminal narrowing.

• Testes

  • Under a tough membranous shell, the tunica albuginea contains very fine coiled tubes called seminiferous tubules.
  • Tunica albuginea, 2.
  • Tunica vaginalis (parietal lamina), 11b.
  • Tunica vaginalis (visceral lamina), and 12.
  • Cavity of tunica vaginalis.