Growth plates (epiphyseal plates) are involved in which process?

• A. Longitudinal bone growth
• B. Matrix mineralization
• C. Articular cartilage formation
• D. Bone resorption by osteoclasts

Answer: (A)

Growth plates are the site where bones lengthen during development. In the epiphyseal plate, cartilage cells continuously proliferate, mature, and hypertrophy, which pushes the bone ends farther apart. Then the surrounding cartilage matrix calcifies and is replaced by bone as osteoblasts invade, a process called endochondral ossification. This sequence adds length to the bone, which is why growth plates drive longitudinal bone growth. Once the plate ossifies and closes, that growth in length stops. Other options don’t capture this primary role: forming articular cartilage happens at joint surfaces, resorption by osteoclasts relates to remodeling, and mineralization occurs as part of ossification rather than being the main function of the growth plate.