Page 46 - Headlines Histology2024_Neat

they are metachromatic (take a different color than the color of the dye
used). The ground substance includes two major groups:
Non-sulfated glycosaminoglycans (hyaluronic acid)

4. The hyaluronic acid consists of long molecule that forms a network whose
spaces are filled with tissue fluid forming gel-like material.

5. The hyaluronic acid predominates in loose connective tissue, vitreous
humor, synovial fluid and umbilical cords.

Sulfated glycosaminoglycans

6. Chondroitin-4-sulfate and chondroitin-6-sulfate are abundant in cartilage,
bone, skin, and cornea.

7. Dermatan sulfate is found in skin, tendon, ligamentum nuchae, sclera and
lung.

8. Keratan sulfate is present in cartilage, bone and cornea.
9. Heparan sulfate in arteries and lung.
10. Heparin in mast cells, in lung, liver and skin.
Functions of the ground substance

11. The glycosaminoglycans and proteoglycans are highly hydrophilic. The
tissue fluid within the meshes permits the diffusion of nutrients and
metabolites between the connective tissue cells and circulatory system.

12. The gel-like nature of the hyaluronic acid is thought to act as a barrier
against the spread of bacteria that may enter the tissues. Invasive bacteria
produce the enzyme hyaluronidase that facilitates their spread.

TYPES OF CONNECTIVE TISSUE
Embryonic connective tissue

Mesenchyme

13. The mesenchyme is primitive embryonic connective tissue from which all
other connective tissue types are derived.

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