Final answer:
The epiphyseal growth plate is composed of five zones: reserve zone, proliferative zone, zone of maturation and hypertrophy, calcification zone, and ossification zone. These zones facilitate the bone's longitudinal growth through various stages of chondrocyte development and ossification.
Step-by-step explanation:
The five zones of the epiphyseal growth plate, which are responsible for the longitudinal growth of bones, are as follows:
- Reserve zone: This is the region closest to the epiphyseal end of the plate, housing small chondrocytes within the matrix that do not participate in active bone growth but anchor the epiphyseal plate to the epiphysis.
- Proliferative zone: Adjacent to the reserve zone towards the diaphysis, this layer contains stacks of chondrocytes that multiply and replenish those that degenerate at the diaphyseal end.
- Zone of maturation and hypertrophy: Here, chondrocytes grow and mature, contributing to the bone's lengthening as they move closer to the diaphysis.
- Calcification zone: In this area, the maturing chondrocytes start to calcify and prepare for ossification.
- Ossification zone: This is where the calcified chondrocytes are replaced by bone cells, eventually leading to the formation of new bone tissue.