Figure 1.

The longitudinal growth of long bone by the growth plate. The growth plate is composed of highly organized and specialized three types of cartilage: the resting, proliferative, and hypertrophic zone. Resting zone chondrocytes supply stem-like cells that give rise to clones of proliferative zone chondrocytes, and determine the spatial orientation of adjacent proliferative columns parallel to the long axis of the bone. The proliferative zone is the region of active cell replication. Hypertrophic zone chondrocytes provide a cartilaginous template, mineralized by their extracellular matrix, supporting the new bone formation by osteoblastic cells. Scale bars indicate 1.25 mm.