reticular fiber

Examples of reticular fiber in the following topics:

• Structural Elements of Connective Tissue

  • Elastic fibers (or yellow fibers) are bundles of proteins (elastin) found in extracellular matrix of connective tissue and produced by fibroblasts and smooth muscle cells in arteries.
  • Elastic fibers include elastin, elaunin, and oxytalan.
  • 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).
  • Reticular fiber is composed of one or more types of very thin and delicately woven strands of type III collagen.

• Characteristics of Connective Tissue

  • Connective tissue fibers provide support.
  • Three types of fires found in connective tissue are collage, elastic fibers and reticular fibers   Collagen fibers are fibrous proteins and are secreted into the extracellular space and they provide high tensile strength to the matrix.
  • Elastic fibers are long, thin fibers that form branching network in the extracellular matrix.
  • Reticular fibers are short, fine collagenous fibers that can branch extensively to forma delicate network.
  • Collagen fibers are the strongest and most abundant of all the connective tissue fibers.

• Blood Supply to the Epidermis

  • The dermis is structurally divided into two areas: a superficial area adjacent to the epidermis, called the papillary region, and a deep thicker area known as the reticular region.
  • The reticular region lies under the papillary region and is usually much thicker.
  • It is composed of dense irregular connective tissue, and receives its name from the dense concentration of collagenous, elastic, and reticular fibers that weave throughout it.
  • These protein fibers give the dermis its typical properties of strength, extensibility, and elasticity.
  • Also located within the reticular region are the roots of the hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels.

• Aging and the Cardiovascular System

  • Movat stain (black = nuclei, elastic fibers; yellow = collagen, reticular fibers; blue = ground substance, mucin; bright red = fibrin; red = muscle).

• Types of Connective Tissue

  • Loose connective tissue is further divided into a) areolar b) adipose c) reticular.
  • Reticular connective tissue: This tissue resembles areolar connective tissue, but the only fibers in its matrix are the reticular fibers which form a  delicate network.
  • Elastic connective tissue: The main fibers that form this tissue are the elastic fibers.
  • These fibers are elastic in nature.
  • These fibers allow the tissues to recoil after stretching.

• Reticular Formation

  • The raphe nuclei form a ridge in the middle of the reticular formation, and directly to its periphery, there is a division called the medial reticular formation.
  • The medial reticular formation is large, has long ascending and descending fibers, and is surrounded by the lateral reticular formation.
  • The nerve fibers in these pathways act in the spinal cord to block the transmission of some pain signals to the brain.
  • Injury to the reticular formation can result in irreversible coma.
  • Reticular formation nuclei that modulate activity of the cerebral cortex are part of the reticular activating system.

• 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 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.
  • Genetic defects in the collagen fibers of the basement membrane cause Alport syndrome or hereditary nephritis, a genetic disorder characterized by glomerulonephritis, endstage kidney disease, and hearing loss.

• Dietary Fiber

  • Lignin, a major dietary insoluble fiber source, may alter the fate and metabolism of soluble fibers.
  • The term "fiber" is something of a misnomer since many types of so-called dietary fiber are not actually fibrous.
  • Dietary fiber is found in plants.
  • Fiber-rich plants can be eaten directly.
  • The plum's skin is a source of insoluble fiber while soluble fiber is in the pulp.

• Structure of the Skin: Dermis

  • The dermis consists of a papillary and a reticular layer which serve to protect and cushion the body from stress and strain.
  • They are the papillary layer and the reticular layer.
  • The upper layer is the papillary layer while the lower layer of the dermis is the reticular layer.
  • The reticular layer serves to strengthen the skin but to also provide our skin with elasticity.
  • The reticular layer also contains hair follicles, sweat glands, and sebaceous glands.

• Overview of Motor Integration

  • A motor unit consists of a single alpha motor neuron and all of the corresponding muscle fibers it innervates; all of these fibers will be of the same type (either fast twitch or slow twitch).
  • When a motor unit is activated, all of its fibers contract.
  • The number of muscle fibers within each unit can vary.
  • Motor units are generally recruited in order of smallest to largest (fewest fibers to most fibers) as contraction increases.
  • These small motor units may contain only 10 fibers per motor unit.