GENERAL FEATURES OF CARTILAGE

Cartilage is a skeletal connective tissue characterized by firmness and resiliency. It forms most of the fetal skeleton and persists in sites where its mechanical properties are needed
Most fetal cartilage eventually becomes bone.
A. Composition: Like all connective tissues, cartilage is composed of cells, fibers, and ground substance. The extracellular matrix predominates and determines cartilage's mechanical properties. Type II collagen is a characteristic cartilage matrix component, and the abundant ground substance is firm and gellike. Cartilage cells are termed chondrocytes.
B. Vascular Supply: Most cartilage is enveloped by a layer of dense connective tissue, the perichondrium, which contains the vascular supply and tibroblastlike stem cells from which additional chondrocytes may arise. Few blood vessels (or nerves) are found within cartilage; thus the composition of the ground substance is crucial to the percolation of nutrients and oxygen to chondrocytes from the surrounding vessels.
C. Cells: Under the light microscope, chondrocytes appear rounded, with an eccentric nucleus, a prominent nucleolus, and basophilic cytoplasm. With EM, chondrocyte surfaces exhibit charac teristic projections and infoldings. The RER and Golgi complex are well developed; the Golgi complex enlarges as the cell grows, and its cisternae fill with secretory material. Some lipid droplets are typically found in the cytoplasm.

Chondrocytes synthesize and secrete the fibers and ground substance of the extracellular matrix: collagen is synthesized on the RER, and GAGs are assembled and sulfated in the Golgi complex.
Because of their meager oxygen supply, chondrocytes produce much of their energy by anaerobic glycolysis