A. Zone of Resting Cartilage
The zone of resting cartilage is the layer of cartilage where the cells are not actively dividing. This zone anchors the epiphyseal plate to the bone and consists of small, inactive chondrocytes. The primary function of this zone is to serve as a stable base that connects the growth plate to the epiphysis of the bone.
B. Zone of Proliferating Cartilage
In the zone of proliferating cartilage, the chondrocytes are actively dividing and forming columns of stacked cells. This zone is crucial for bone growth because it contributes to the lengthening of the bone. As the cells divide and multiply, they produce new cartilage, pushing the older cells toward the next zone.
C. Zone of Hypertrophic Cartilage
The zone of hypertrophic cartilage is where the chondrocytes begin to mature and enlarge. In this zone, the cells experience significant growth and increase in size before they undergo further changes. This zone plays a vital role in the maturation process of the cartilage cells, which is essential for the subsequent ossification that leads to bone formation.
D. Zone of Calcified Cartilage
Lastly, the zone of calcified cartilage consists of dead chondrocytes that have been replaced by bone tissue. In this area, the extracellular matrix becomes calcified, and the cartilage is transformed into bone. This zone is critical during the growth process as it allows for the replacement of cartilage with bone, contributing to the overall increase in bone length and strength.