Part 1. BIOCHEMISTRY OF CONNECTIVE TISSUE

Main subjects:

1.1. Glycosaminoglycans

1.2. Collagens

1.3. Elastin

1.4. Adhesive proteins

1.5. Mineralized connective tissue

1.6. Mineral composition and structure of apatites in the hard tissue

1.7. Organic matter of mineralized tissues

1.8. Bone tissue remodeling

1.9. Regulation of remodeling, growth and development of bone tissue

1.10. Markers of bone tissue metabolism

1.11. Features of dental tissue structure and metabolism

Human tissues are composed not only of cells. Most mammalian cells are located in tissues, where they are surrounded by a complex extracellular matrix. The matrix includes different polysaccharides and proteins spontaneously organized to form ordered structures. The tissue in which extracellular matrix occupies a considerably larger volume than cells is often referred to as "connective tissue" (Fig. 1.1).

Fig. 1.1. Organization: extracellular matrix-basal membrane-epithelium

The connective tissue contacts with the layer of epithelial cells. The basal membrane (very thin and stiff film) resides between epithelium and extracellular matrix.

Connective tissue provides:

► active exchange of metabolites and ions between the blood and tissues;

► formation of the structure of organs and tissues during embryogenesis and the postnatal period;

► flexibility of interacting surfaces ofjoints because it forms cartilage;

► protection against external influence by regulation of the functional activity of phagocytes and immune system cells;

► regeneration and replacement of imperfection by stimulating functional activity and proliferation of tissue cells.

The share of connective tissue varies in different organs: in bones and skin it is the main component. Connective tissue may be mineralized forming hard bone or tooth structures; and also form transparent matter of eye cornea, or a cord-like structure making tendons resistant to rupture.