Histolec2-connective Tissue

CON NECT IV E TIS SUE

Components 1. Cellular component a. fibroblast b. fat cells c. white blood cell derivatives 2. Fibrous component – collagen, elastin, reticular 3. Ground substance

Fibroblast - most common cell - Single,spindle shaped , elongated - Secretes : fibrous component ground substance

Fibers • Collagen fibers - most abundant protein in human body - fibrillar proteins secreted by fibroblast - amino acids : glycine, proline, hydroxyproline - protein unit: tropocollagen

Reticular fibers - Thinnest - Network of fibers - Argyrophilic fibers - Type III collagen - Location: smooth muscle , endoneurium hematopoetic organs parenchymal organs

Elastic fibers - 3 types of fibers: oxytalan, elaunin, elastin - Location: smooth muscle cells walls of large arteries

Ground Substance • Composition : a. glycoproteins – fibronectin, laminin, chondronectin b. proteoglycans – core protein + GAG

Glycosaminoglycans • 4 groups: a. hyaluronic acid b. heparin and heparan sulfate c. chondroitin sulfate dermatan sulfate d. keratan sulfate

PROTEOGLYCAN STRUCTURE & H2O-BINDING Sugar side-chains of repeating pairs (disaccharides)

SO4

Core protein Side chains bear

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H2O SO4

SO4

-XL-GA-GU-GA-GU-GA-GU-GA-GUco o H2O -binding

charged groups

which mutually repel, but cannot disperse because of O2 bonds & anchorage to the core protein