Bone grows via a process of apposition and resorption on its surface. Which cells are responsible for the resorption of bone during its growth or repair?

Bone grows via a process of apposition and resorption on its surface. Which cells are responsible for the resorption of bone during its growth or repair?

• A. Osteoclasts
• B. Osteoblasts
• C. Osteocytes
• D. Chondroblasts

Answer: (A)

The process relies on osteoclasts performing bone resorption. These large, multinucleated cells attach to the bone surface and create a sealed resorption zone. They secrete acids to dissolve the mineral component (hydroxyapatite) and release proteolytic enzymes like cathepsin K to break down the organic matrix. This resorption clears old or damaged bone and shapes the surface so osteoblasts can lay down new bone, which then mineralizes. Other cells have different roles: osteoblasts form bone, osteocytes are mature bone cells embedded in the matrix, and chondroblasts produce cartilage in cartilage-based growth, but they do not resorb bone.

The process relies on osteoclasts performing bone resorption. These large, multinucleated cells attach to the bone surface and create a sealed resorption zone. They secrete acids to dissolve the mineral component (hydroxyapatite) and release proteolytic enzymes like cathepsin K to break down the organic matrix. This resorption clears old or damaged bone and shapes the surface so osteoblasts can lay down new bone, which then mineralizes. Other cells have different roles: osteoblasts form bone, osteocytes are mature bone cells embedded in the matrix, and chondroblasts produce cartilage in cartilage-based growth, but they do not resorb bone.