Connective and supporting tissues

Connective and supporting tissues

• are remarkable for well-developed intercellular substance with a heterogenous chemical composition and structure that depend on tissue type
• differ by the number of tissue-forming cell lineages (there can be one or more cell lineages)
• take part in maintaining homeostasis (steady internal environment) by exerting transport, trophic, protective, biomechanical (supporting), and plastic functions
• are derived from the mesenchyme

Intercellular substance (extracellular matrix) is produced by cells. It contains fibers and the ground (amorphous) substance

Fibers

• are formed by fibrous proteins, namely by collagen type I (loose and dense connective tissue, osseous tissue, dentine and cement of teeth) and type II (cartilage tissue)
• exhibit a higher strength and no potential to be stretched
• join into bundles, ensure the architecture and mechanical properties of connective tissues

• are formed by collagen type III (reticular tissue, loose connective tissue)
• are stained by silver salts, so these fibers are called argyrophilic
• construct 3D-networks and thus exert a sustentacular function

• are formed by such proteins as elastin and fibrillin
• are selectively stained by orcein and aldehyde-fuchsin
• branch and form anastomoses, ensure a potential for reversible deformation in connective tissue

Ground (amorphous) substance

• is constituted by macromolecular complexes of proteoglycans and glycoproteins
• can be hydrated or mineralized
• fills spaces between cells and fibers, participates in exerting the transport, trophic, and sustentacular function

Classification of connective and supporting tissues

Functional determination of connective and supporting tissues

Mesenchyme

• is formed during the embryogenesis by cell migration from the mesoderm (endomesenchyme) and neuroectoderm (ectomesenchyme)
• is a group of various cells (different in their determination) and jelly-like intercellular substance
• undergoes cell differentiation that depends on the surrounding cells

Mesenchyme