Final answer:
Bone repair after a fracture involves a hematoma formation, followed by the activity of osteoclasts to remove dead bone and osteoblasts to build new bone, leading to the formation of a bony callus that gets remodeled into compact bone.
Step-by-step explanation:
When a bone fracture occurs, the subsequent repair process involves several biological mechanisms. Initially, blood vessels in the fractured bone hemorrhage, forming a hematoma. Eventually, osteoclasts break down the dead bone while osteoblasts work on new bone formation. Initially, a fibrocartilaginous callus forms which later gets replaced by a bony callus of spongy bone. This turns into compact bone as osteoblasts and osteoclasts remodel the fracture site, a process that can last several months.
Throughout life, bones undergo continual remodeling, where osteoclasts resorb old bone and osteoblasts lay down new bone. This process shapes the skeleton, repairs flaws, and maintains mineral homeostasis. Compact bone is denser and forms the bone's outer layer, while spongy bone, consisting of trabeculae, forms the inner layer.