Which cell type forms bone by deposition of matrix?

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

Answer: (B)

Bone formation by laying down the organic matrix is carried out by osteoblasts. These cells synthesize and secrete osteoid, the organic component rich in collagen type I and other proteins, which forms the scaffold for mineral deposition. They also release enzymes and factors that promote mineralization, allowing calcium phosphate crystals to harden the matrix into bone. Once osteoblasts become embedded in the newly formed matrix, they mature into osteocytes, which help maintain the bone tissue. In contrast, osteoclasts break down bone, and chondrocytes produce cartilage rather than bone matrix.