Development
Development
Cartilage is the precursor for most bones in our skeleton. At lower levels of the evolution some animals have cartilaginous skeleton rather than bony skeleton (e.g., sharks). During embryonic development the human skeleton most of the bones develop from a cartilaginous precursor structure which during a complex modification becomes bony tissue (only few exceptions, such as the skull, clavicle, and pelvic bones).
As blood vessels break into the cartilage tissue it soon transforms into bone tissue. This process, however, does not apply to the whole affected bone, as narrow zones of cartilage (growth plate, physis) remain until the completion of growth. Widening of long bones during growth is completed by the cells in the periosteum, fracture healing is done by bone cells, hence cartilage has no function in these two processes.
