Final answer:
The cartilage in the epiphyseal plates facilitates the lengthwise growth of long bones during development. It involves the formation of new cartilage and its subsequent ossification into bone, which ceases once adolescence is reached and the epiphyseal plate is fully ossified into the epiphyseal line.
Step-by-step explanation:
Function of Cartilage in the Epiphyseal Plates
The epiphyseal plate, also known as the growth plate, is crucial in the lengthwise growth of long bones. Cartilage in the epiphyseal plates serves as a precursor to bone tissue. Within these plates, new cartilage is continually formed on the epiphyseal side, while on the diaphyseal side, cartilage is ossified, thereby allowing the bone to lengthen. The process involves several distinct zones of activity:
The reserve zone secures the cartilage to the epiphysis and does not directly contribute to bone growth.
The zone of proliferation is where chondrocytes divide and increase the thickness of the epiphyseal plate.
The zone of maturation and hypertrophy is where chondrocytes grow and prepare for calcification.
The zone of calcified matrix connects the plate to the diaphysis and is where the actual conversion of cartilage to bone occurs, contributing to the growth in length of the bone.
This growth process is regulated by hormones and continues until early adulthood when the chondrocytes stop proliferating and the cartilage is fully replaced by bone. This is marked by the appearance of the epiphyseal line.