Final answer:
Bone resorption is primarily driven by parathyroid hormone (PTH), cortisol, and thyroid hormones, with PTH being a key factor in stimulating osteoclasts to resorb bone.
Step-by-step explanation:
Bone resorption is a biological process where old bone tissue is broken down and absorbed into the body. The primary hormones driving bone resorption include parathyroid hormone (PTH), cortisol, and thyroid hormones. PTH, in particular, is critical for this process as it stimulates osteoclast proliferation and the actual resorption of bone by these osteoclasts. Cortisol has various functions in the body, including the suppression of bone formation, and thyroid hormones are known to have multiple effects on bone remodeling, working synergistically with PTH.
Calcitonin, on the other hand, has the opposite effect by inhibiting osteoclast activity, which reduces bone resorption and prompts the uptake of calcium by the bones. Other hormones also play significant roles in bone metabolism, such as growth hormone and sex steroids like estrogen and testosterone, which are more involved in promoting osteoblastic activity and the production of bone matrix instead of bone resorption.
As we age, bone resorption can become more pronounced—leading to conditions such as osteoporosis; PTH plays an essential role in this age-related increase in bone resorption, especially when there is a deficiency of calcium or vitamin D.