Summary
Osteoclasts resorb and osteoblasts build bone continuously, controlled by hormones and stress.
In depth
Wolff's law: bone adapts to load. Parathyroid hormone raises blood calcium by activating osteoclasts; calcitonin lowers it. Osteoporosis arises when resorption outpaces formation, common after menopause.
Mechanical loading strengthens bone. Calcium and vitamin D are needed. Hormones such as oestrogen protect bone.
Example: weight-bearing exercise helps prevent osteoporosis.
Bone is renewed constantly, and about 10 percent of the skeleton is replaced each year, with the entire adult skeleton remodelled about every 10 years. Osteoclasts dissolve bone with acid and enzymes, then osteoblasts lay down osteoid collagen that mineralises with hydroxyapatite. Osteocytes sense strain and signal through sclerostin. Hormones: PTH raises calcium, vitamin D increases absorption in gut, calcitonin lowers calcium (minor in adults), oestrogen restrains osteoclasts, so menopause speeds bone loss.
Osteoporosis treatment includes bisphosphonates (inhibit osteoclasts), denosumab, teriparatide and calcium, vitamin D and exercise. Fractures heal by haematoma, soft callus, hard callus and remodelling over months. Astronauts lose bone mass in weightlessness.
Frequently asked questions
What is Bone Remodelling?
Osteoclasts resorb and osteoblasts build bone continuously, controlled by hormones and stress.
Which area of biology covers Bone Remodelling, and how advanced is it?
Bone Remodelling is one of the 51 topics in Human Physiology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Skeletal System, Exercise Adaptations, Blood Pressure.
Why does Bone Remodelling matter?
Peak bone mass reached around age 30 determines later fracture risk.
Can you give an example of Bone Remodelling?
Astronauts lose bone density in microgravity.
What should I learn before Bone Remodelling?
Work through the Beginner topics in Human Physiology first, such as Homeostasis, Tissues and Organs, Skeletal System, then return to Bone Remodelling. Intermediate topics assume the Beginner vocabulary.
What topics are related to Bone Remodelling?
The closest topics to Bone Remodelling are Skeletal System, Exercise Adaptations, Blood Pressure, Blood Glucose Regulation. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Bone Remodelling?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Bone Remodelling. To practise the whole of Human Physiology, use the Human Physiology quiz.
How is Bone Remodelling different from Skeletal System?
Bone Remodelling: Osteoclasts resorb and osteoblasts build bone continuously, controlled by hormones and stress. Skeletal System: Bones, cartilage and joints that support the body, protect organs and allow movement. Read both side by side and note what each one explains.
How should I study Bone Remodelling step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Skeletal System and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.