Endochondral bone, Growth plate, diagram
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Levels of the growth plate (epiphyseal plate), diagram. In the proliferative zone (P) most if not all chondrocyte division occurs. In the hypertrophic zone (H), chondrocytes mature and release matrix vesicles into the longitudinal septal matrix (LS) during its formation. In the calcifying zone (C), mineralization first occurs in the longitudinal septa within matrix vesicles. Most chondrocytes undergo apoptosis in the calcifying zone. Invading capillaries from the metaphysis (M), resorb the columns of apoptotic chondrocytes and transverse septal matrix leaving longitudinal spicules of calcified cartilage projecting into the metaphysis. These spicules serve as a lattice upon which new bone matrix is deposited by osteoblasts.