What is the effect of sex hormones on bone growth?

• A. They stimulate osteoclast activity
• B. They close epiphyseal plates
• C. They increase calcium absorption
• D. They enhance cartilage cell division

Answer: (B)

Sex hormones, particularly estrogen and testosterone, play a significant role in bone growth and development. One of their key effects is the closure of epiphyseal plates, which are the growth plates located at the ends of long bones. During puberty, an increase in sex hormone levels leads to a stimulation of osteoblast activity, which increases bone formation. Concurrently, these hormones also influence the signaling that causes the epiphyseal plates to ossify, or close, halting further lengthening of the bones. This process is critical for the attainment of peak bone mass and affects overall skeletal maturity.

The closure of the epiphyseal plates marks the end of longitudinal bone growth. This process is essential in regulating height and is a natural part of skeletal development during adolescence. Thus, understanding the impact of sex hormones on bone structure is vital for insights into both growth disorders and conditions like osteoporosis, where hormonal balance is disrupted.