Which cell type is primarily involved in bone resorption during remodeling?

Which cell type is primarily involved in bone resorption during remodeling?

• A. Osteoclast
• B. Osteoblast
• C. Osteocyte
• D. Chondrocyte

Answer: (A)

In bone remodeling, removing old bone is done by osteoclasts. These large, multinucleated cells come from the monocyte/macrophage lineage and attach to the bone surface to form a sealed resorption zone. They acidify the space to dissolve mineral and release proteolytic enzymes like cathepsin K to break down the organic matrix. After resorption, osteoblasts move in to lay down new osteoid and mineralize it, completing the cycle. Osteoblasts are the builders, osteocytes act as sensors and regulators within the bone matrix, and chondrocytes form cartilage (not the mineralized bone being remodeled). So the cell primarily responsible for bone resorption is the osteoclast.

In bone remodeling, removing old bone is done by osteoclasts. These large, multinucleated cells come from the monocyte/macrophage lineage and attach to the bone surface to form a sealed resorption zone. They acidify the space to dissolve mineral and release proteolytic enzymes like cathepsin K to break down the organic matrix. After resorption, osteoblasts move in to lay down new osteoid and mineralize it, completing the cycle. Osteoblasts are the builders, osteocytes act as sensors and regulators within the bone matrix, and chondrocytes form cartilage (not the mineralized bone being remodeled). So the cell primarily responsible for bone resorption is the osteoclast.