University:
Kentucky State University
Course:
BIO 301 | Human Anatomy
Academic year:

2023
Views:

46

Pages:

22
Author:

hekeldigzjbz

Connective Tissue Fibers Properties Collagen Undulating course of longitudinally striated bundles, form meshwork of variable texture, stain pink-red in H&E. Nonextensile. Elastic Forms sheets or lamina, Unstained in H & E. Reversibly extensible. Stains brown-black in Orcein, Resorscin Fuchsin, and Verhoeff-van Gieson’s Reticular Delicate network, Unstained in H & E. Reversibly extensible. PAS +ve, stains black in AgNO3 (Argyrophilic). Collagen types • Fibrillar collagens, notably collagen types I, II, and III. Form structures such as tendons, organ capsules, and dermis. • Network or sheet-forming collagens such as type iv collagen have subunits produced by epithelial cells and are major structural of external laminae and all epithelial basal laminae. • Linking/anchoring collagens are short. COLLAGEN ASSEMBLY 1. Rodlike triple-helix collagen molecules, each 300-nm long, selfassemble in a highly organized, lengthwise arrangement of overlapping regions. 2. The regular, overlapping arrangement of subunits continues as large collagen fibrils are assembled. 3. This structure causes fibrils to have characteristic cross striations with alternating dark and light bands when observed in the EM. 4. Fibrils assemble further and are linked together in larger collagen fibers visible by light microscopy. 5. Type I fibers often form into still larger aggregates bundled and linked together by other collagens. RETICULAR FIBERS Ground substance • A semi- fluid gel (highly hydrated) and transparent material. • Function: medium for passage/exchange of molecules and metabolites. • Composed of: glycosaminoglycans (gags(mucopolysaccharides)), proteoglycans, and multiadhesive glycoproteins (structural glycoproteins:laminin, fibronectin, integrin) GAGs that form proteoglycans • Hyaluronic acid • Chondroitin 4-sulfate • Chondroitin 6-sulfate • Dermantan sulfate • Heparan sulfate • Heparin • Keratan sulfate GAGs Classification Of Connective Tissue Connective tissue Embryonic connective tissue Mesenchyme Loose (areolar) connective tissue Adult connective tissue Dense connective tissue Mucous Regular Irregular Specialized Reticular Adipose Bone Cartilage Blood Classification-Embryonic Classification-Adult Classification-Specialized Embryonic Connective Tissue • Mesenchyme connective tissue • Mucous connective tissue Mesenchyme Mucous Connective Tissue Loose (Areolar) Connective Tissue • Consists of all 3 types of fibers, several types of cells, and semi-fluid ground substance. • Found in subcutaneous layer and mucous membranes, and around blood vessels, nerves and organs • Function = strength, support and elasticity Dense Connective Tissue Contains more numerous and thicker fibers and far fewer cells than loose CT. a. Dense regular connective tissue Tendons and ligaments b. Dense irregular connective tissue Dermis of skin Dense Regular Connective Tissue • Consists of bundles of collagen fibers and fibroblasts. • Forms tendons, ligaments. • Function = provide strong attachment between various structures. Dense Irregular Connective Tissue Dense Irregular CT • Consists Of Randomlyarranged Collagen Fibers And A Few Fibroblasts. • Found In Dermis Of Skin • Function = Provide Strength Elastic Connective Tissue RETICULAR CT • Consists Of Fine Interlacing Reticular Fibers And Reticular Cells. • Found In Liver, Spleen And Lymph Nodes. • Function = Forms The Framework (Stroma) Of Organs And Binds Together Smooth Muscle Tissue Cells.