Which bone cell is responsible for bone resorption?

Which bone cell is responsible for bone resorption?

• A. Osteoblasts
• B. Osteocytes
• C. Osteoclasts
• D. Osteoprogenitor cells

Answer: (C)

Bone resorption is carried out by osteoclasts. These large, multinucleated cells attach to the bone surface and create a sealed zone where they secrete acid and proteolytic enzymes (like cathepsin K) to dissolve mineral and organic matrix. This activity removes old or damaged bone and forms Howship lacunae, setting the stage for new bone to be laid down. The process is regulated by signals from other bone cells, notably RANKL from osteoblast lineage promoting osteoclast formation and activity, with OPG acting as a decoy receptor to dampen it. In contrast, osteoblasts form new bone by laying down osteoid that mineralizes, osteocytes are mature cells embedded in the bone matrix that sense mechanical strain and coordinate remodeling, and osteoprogenitor cells can differentiate into osteoblasts. So the cells responsible for resorption are the osteoclasts.

Bone resorption is carried out by osteoclasts. These large, multinucleated cells attach to the bone surface and create a sealed zone where they secrete acid and proteolytic enzymes (like cathepsin K) to dissolve mineral and organic matrix. This activity removes old or damaged bone and forms Howship lacunae, setting the stage for new bone to be laid down. The process is regulated by signals from other bone cells, notably RANKL from osteoblast lineage promoting osteoclast formation and activity, with OPG acting as a decoy receptor to dampen it. In contrast, osteoblasts form new bone by laying down osteoid that mineralizes, osteocytes are mature cells embedded in the bone matrix that sense mechanical strain and coordinate remodeling, and osteoprogenitor cells can differentiate into osteoblasts. So the cells responsible for resorption are the osteoclasts.