elastic lamina

Examples of elastic lamina in the following topics:

• Muscular Arteries

  • Distributing arteries are medium-sized arteries that draw blood from an elastic artery and branch into resistance vessels.
  • Muscular or distributing arteries are medium-sized arteries that draw blood from an elastic artery and branch into resistance vessels, including small arteries and arterioles.
  • In contrast to the mechanism elastic arteries use to store and dissipate energy generated by the heart's contraction, muscular arteries contain layers of smooth muscle providing allowing for involuntary control of vessel caliber and thus control of blood flow.
  • 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.

• 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.
  • Fiber composition also differs; veins contain fewer elastic fibers and function to control caliber of the arteries, a key step in maintaining blood pressure.
  • 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.
  • This diagram of the artery wall indicates the smooth muscle, external elastic membrane, endothelium, internal elastic membrane, tunica externa, tunica media, and tunica intima.

• Hemidesmosomes

  • Anchoring filaments traverse the lamina lucida space and appear to insert into the electron dense zone, the lamina densa.
  • Beneath the lamina densa, loop-structured, cross-banded anchoring fibrils extend more than 300 nm beneath the basement membrane within the papillary dermis.
  • The length of these loops may enable them to link or encircle dermal collagen fibers or other components such as those of the elastic microfibril network.
  • In a normal mouse (a) there are well-defined, organized hemidesmosomes with darkened areas in the lamina densa abutting the hemidesmosome (arrows).

• Basement Membranes and Diseases

  • The basement membrane is the fusion of two lamina: the basal lamina and the reticular lamina (or lamina reticularis).
  • The lamina reticularis is attached to the basal lamina with anchoring fibrils (type VII collagen fibers ) and microfibrils (fibrillin).
  • The basal lamina layer can further be divided into two layers: the clear layer closer to the epithelium is called the lamina lucida, and the dense layer closer to the connective tissue is called the lamina densa.
  • The electron-dense lamina densa membrane is about 30–70 nanometers in thickness, and consists of an underlying network of reticular collagen (type IV) fibrils (fibroblast precursors) which average 30 nanometers in diameter and 0.1–2 micrometers in thickness.
  • The most notable examples of basement membranes are in the glomerular filtration of the kidney, by the fusion of the basal lamina from the endothelium of glomerular capillaries and the basal lamina of the epithelium of the Bowman's capsule; and between lung alveoli and pulmonary capillaries, by the fusion of the basal lamina of the lung alveoli and of the basal lamina of the lung capillaries, which is where oxygen and CO2 diffusion happens.

• Epithelial Membranes

  • It consists of an epithelium layer and an underlying lamina propria of loose connective tissue.
  • The epithelial tissue sheet lies directly over the layer of loose connective tissue called lamina propria.
  • In some mucosa, the lamina propria rests on a deeper, third layer of smooth muscle.

• Elastic Arteries

  • An elastic or conducting artery has a large number of collagen and elastin filaments in the tunica media.
  • The pulmonary arteries, the aorta, and its branches together comprise the body's system of elastic arteries.
  • 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.
  • In elastic arteries, the tunica media is rich with elastic and connective tissue.
  • The aorta makes up most of the elastic arteries in the body.

• Parts of a Vertebra

  • The vertebral arch is formed from two, short, thick processes called pediments that extend posteriorly from the lateral sides of the vertebral body, before joining together at the midline with the laminae.
  • Four articular processes originate from the joint between the pedicles and laminae, two point superiorly and two point inferiorly. 
  • The two transverse processes project laterally from the join between the pedicle and lamina and also serve as an attachment point for muscles and ligaments of the back.

• Capillaries

  • They are surrounded by a thin basal lamina of connective tissue.
  • These types of blood vessels allow red and white blood cells (7.5μm - 25μm diameter) and various serum proteins to pass using a process aided by a discontinuous basal lamina.
  • Capillaries are surrounded by a thin basal lamina of connective tissue.

• Mucosa

  • The mucosa is made up of three layers: epithelium, lamina propria, and muscularis mucosae.
  • The lamina propria is a layer of connective tissue that is unusually cellular compared to most connective tissue.