elastic fiber

Examples of elastic fiber in the following topics:

• Connective Tissues: Loose, Fibrous, and Cartilage

  • The organic portion, or protein fibers, found in connective tissues are either collagen, elastic, or reticular fibers.
  • Collagen fibers are relatively wide and stain a light pink, while elastic fibers are thin and stain dark blue to black .
  • A cartilage with few collagen and elastic fibers is hyaline cartilage.
  • Elastic cartilage has a large amount of elastic fibers, giving it tremendous flexibility.
  • Loose connective tissue is composed of loosely-woven collagen and elastic fibers.

• Structural Elements of Connective Tissue

  • Elastic fibers include elastin, elaunin, and oxytalan.
  • Elastic tissue is classified as "connective tissue proper. " The elastic fiber is formed from the elastic microfibril and amorphous elastin.
  • Elastic fibers are found in the skin, lungs, arteries, veins, connective tissue proper, elastic cartilage, periodontal ligament, fetal tissue, and other structures.
  • Reticular fibers or reticulin is a histological term used to describe a type of fiber in connective tissue composed of type III collagen.
  • Reticular fibers crosslink to form a fine meshwork (reticulin).

• 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.

• Structure, Type, and Location of Cartilage

  • Elastic or yellow cartilage contains elastic fiber networks and collagen fibers.
  • Elastic cartilage is histologically similar to hyaline cartilage but contains many yellow elastic fibers lying in a solid matrix.
  • These fibers form bundles that appear dark under a microscope.
  • They give elastic cartilage great flexibility so it can withstand repeated bending.
  • Chondrocytes lie between the fibers.

• The Work of Breathing

  • Breathing includes several components, including flow-resistive and elastic work; surfactant production; and lung resistance and compliance.
  • There are two types of work conducted during respiration: flow-resistive and elastic work.
  • When the respiratory rate is decreased, the flow-resistive work is decreased and the elastic work is increased.
  • The overall compliance of the lungs is increased, because as the alveolar walls are damaged, lung elastic recoil decreases due to a loss of elastic fibers; more air is trapped in the lungs at the end of exhalation.
  • Explain the roles played by surfactant, flow-resistive and elastic work, and lung resistance and compliance in breathing

• 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.
  • In these large arteries, the amount of elastic tissue is considerable and the smooth muscle fiber cells are arranged in 5 to 7 layers in both circular and longitudinal directions.
  • 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.

• Types of Connective Tissue

  • Dense connective tissue is divided into 1) dense regular, 2) dense irregular, 3) elastic.
  • This tissue resembles areolar connective tissue, but the only fibers in its matrix are the reticular fibers, which form a delicate network.
  • The main fibers that form this tissue are elastic in nature.
  • These fibers allow the tissues to recoil after stretching.
  • This is similar to hyaline cartilage but is more elastic in nature.

• Muscle Attachment Sites

  • At either end of the tendon, its fibers intertwine with the fascia of a muscle or the periosteum (a dense fibrous covering of a bone), allowing force to be dissipated across the bone or muscle.
  • Tendons mainly consists of closely-packed collagen fibers running parallel to the force generated by the muscle to which they are attached.
  • Intertwined with the collagen fibers are elastin molecules, which improve the tendons' elasticity, and various proteoglycans, proteins to which many carbohydrate molecules are attached.
  • However, research into their elastic properties has demonstrated that they can also act as springs.
  • The elasticity of tendons allows them to passively store energy for later release.

• Arrangement of Fascicles

  • Skeletal muscles are grouped into fascicles, which are bunches of muscle fibers surrounded by a perimysium.
  • Skeletal muscle tissue is composed of numerous muscle fibers which are separated from adjacent muscles and other tissues by a layer of dense, elastic connective tissue termed the fascia.
  • Muscle fascia is predominately composed of cross-linked collagen and elastin fibers oriented parallel to the direction of muscle force, making them able to resist high-tension forces while remaining somewhat elastic.
  • It extends inwards and becomes the perimysium, then into the muscle separating muscle fibers into small bundles termed fascicles.
  • Each individual fiber within a fascicle is surrounded by a thin connective layer termed the endomysium, which helps maintain close association between the muscle fiber and associated vascular and nervous systems.

• Urinary Bladder

  • The urinary bladder is a hollow, muscular, and distendible or elastic organ that sits on the pelvic floor.
  • The bladder is a hollow, muscular, and elastic organ that sits on the pelvic floor.
  • A normal bladder empties completely upon a complete discharge, otherwise it is a sign that its elasticity is compromised; when it becomes completely void of fluid, it may cause a chilling sensation due to the rapid change of body temperature.
  • The bladder receives motor innervation from both sympathetic fibers, most of which arise from the hypogastric plexuses and nerves, and parasympathetic fibers, which come from the pelvic splanchnic nerves and the inferior hypogastric plexus.
  • Sensation from the bladder is transmitted to the central nervous system (CNS) via general visceral afferent fibers.