Final answer:
Hormones such as GH, IGF-1, thyroid hormone, and sex hormones promote bone formation and growth.
Step-by-step explanation:
Hormones such as growth hormone (GH), insulin-like growth factor (IGF-1), thyroid hormone, and sex hormones (estrogen and testosterone) play a role in bone formation. GH triggers the proliferation of chondrocytes in the epiphyseal plates, which leads to increased bone length. IGF-1 activates the production of bone cells called osteocytes. Thyroxine promotes osteoblastic activity and the synthesis of bone matrix. Estrogen and testosterone promote osteoblastic activity, production of bone matrix, and the growth spurt during adolescence. They also convert the cartilage in the epiphyseal plates to bone, ending longitudinal bone growth.