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An osteoclast (from Ancient Greek ὀστέον (osteon) 'bone' and κλαστός (clastos) 'broken') is a type of bone cell that breaks down bone tissue.This function is critical in the maintenance, repair, and remodeling of bones of the vertebral skeleton.
It is the most common reason for a broken bone among the elderly. [3] Bones that commonly break include the vertebrae in the spine, the bones of the forearm, the wrist, and the hip. [8] [9] Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously.
Bone tissue is a dynamic system with active metabolism. [24] Bone tissue remodelling or bone remodeling is a successive chain of old bone matrix removal and its replacement with a new one. [25] These processes make a child’s skeleton grow and extend, while childhood is characterized by bone tissue growth rather than its resorption.
Bone is broken down by osteoclasts, and rebuilt by osteoblasts, both of which communicate through cytokine (TGF-β, IGF) signalling. Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. [1]
The osteoblasts form new lamellar bone upon the recently exposed surface of the mineralized matrix. This new lamellar bone is in the form of trabecular bone. Eventually, all of the woven bone and cartilage of the original fracture callus is replaced by trabecular bone, restoring most of the bone's original strength. [citation needed]
"Bones break because of either two main reasons. One, the force on the broken is stronger than the bone can take. Or two, the bone itself is weakened for some reason," said Dr. Claire Shannon, a ...
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Osteoclasts break down bone tissue, and along with osteoblasts and osteocytes form the structural components of bone. In the hollow within bones are many other cell types of the bone marrow . Components that are essential for osteoblast bone formation include mesenchymal stem cells (osteoblast precursor) and blood vessels that supply oxygen and ...