Which cell type forms new bone by secreting osteoid on bone surfaces?

Which cell type forms new bone by secreting osteoid on bone surfaces?

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

Answer: (A)

Bone formation on surfaces is carried out by osteoblasts, which secrete osteoid—the organic matrix rich in collagen type I. This osteoid is laid down on existing bone surfaces and later mineralizes to become bone. Osteoblasts line the surface of forming bone in areas such as the periosteum and endosteum. Once the matrix is mineralized and the cells become embedded, they differentiate into osteocytes housed in lacunae. In contrast, osteoclasts resorb bone, and chondrocytes produce cartilage rather than bone. So the cell responsible for forming new bone by secreting osteoid on bone surfaces is the osteoblast.

Bone formation on surfaces is carried out by osteoblasts, which secrete osteoid—the organic matrix rich in collagen type I. This osteoid is laid down on existing bone surfaces and later mineralizes to become bone. Osteoblasts line the surface of forming bone in areas such as the periosteum and endosteum. Once the matrix is mineralized and the cells become embedded, they differentiate into osteocytes housed in lacunae. In contrast, osteoclasts resorb bone, and chondrocytes produce cartilage rather than bone. So the cell responsible for forming new bone by secreting osteoid on bone surfaces is the osteoblast.