Electron microscopic study of chondroid tissue in the cat mandible.

This paper deals with electron microscopic appearance of chondroid tissue. Samples from eight cat mandibles were studied without decalcification. The ultrastructural characteristics of the chondroid tissue cells are common with young osteocytes. The interterritorial matrix of chondroid tissue is mineralized, being constituted of large collagen fibrils and calcospherites. The compositions of these parts of the chondroid tissue matrix and of bony matrix are similar but they are two different tissues. The pericellular matrix of the chondroid tissue consists of finely branched filaments, thin collagen fibrils, and an abundant ground substance. It resembles a cartilage matrix and contains type II collagen which is not present in bony matrix.