CONNECTIVE TISSUE FIBERS

Author: Dr. R. Menaka

.............................................................................................................

A. Collagen fibers:

    With the light microscope collagen fibers are seen in bundles. The bundles are made up of collections of individual collagen fibers which are 1-12 micrometer in diameter. The bundles often branch or anastomose with adjacent bundles, but the individual fibers donot branch.

    Bundles of collagen fibers appear white with the naked eye. In sections stained with haematoxylin and eosin collagen fibers are stained light pink.

Special Method of Staining - Collagen fibers

Masson's Trichrome - in which the collagen fibers are stained blue.

Van Gieson Method- in which the collagen fibers are stained pink

After silver impregnation the collagen fibers are stained brown.

    Collagen fibers are made up of mainly of a protein called Collagen. Several types of collagen are recognized depending upon the diameter of fibers, the prominence of cross striations and other features.

Type- I Collagen- e.g. Tndon, ligaments, fasciae and aponeurosis etc. They are also present in the dermis of the skin and in meninges.

Type-II Collagen - e.g. Hyaline cartilage and vitreous body

Type-III Collagen - These forms reticular fibers

Type-IV Collagen - Collagen fibers found in the lens capsule.

B. Reticular fibers:

     They can be stained specially by silver impregnation which renders them black. Reticular fiber shows affinity for silver salts. Because of this property, the reticular fibers known as argentophil fibers. e.g. Spleen, lymphnode, bone marrow, most glands, liver and kidney. Reticular fibers form an essential component of all basement membranes. They  are also found in relation to smooth muscle and nerve fibers.

C. Elastic fibers:

    Elastic fibers donot stain with the usual stains for collagen. They can be demonstrate by staining with orcein with aldehyde fuchsin and by Verheoff's method.

    Elastic fibers are composed of a protein called elastin which forms this central amorphous core. Elastin is made up of smaller unit known as tropoelastin. Elastic fibers of connective tissue are produced by fibroblasts. In some situations elastic tissue can be formed by smooth muscle cells.

Muscular Tissue                                                                      Back to Home