Bone-forming cells that secrete unmineralized bone matrix (osteoid) and are actively mitotic.

Bone-forming cells that secrete unmineralized bone matrix (osteoid) and are actively mitotic.

• A. Osteogenic Cells
• B. Osteoblasts
• C. Osteocytes
• D. Osteoclasts

Answer: (B)

Osteoblasts are the bone-forming cells that secrete the unmineralized bone matrix, called osteoid. They line the surfaces of growing bone and produce the organic component mostly made of collagen type I and other proteins. This osteoid is later mineralized to become mature bone. Osteoblasts originate from osteogenic (osteoprogenitor) cells, which are mitotically active stem cells found in the periosteum and endosteum; when they divide and differentiate, they become osteoblasts. Once the matrix is laid down, some osteoblasts stay on the surface as lining cells, some become embedded in the matrix and differentiate into osteocytes, and others may contribute to further growth. In contrast, osteocytes are mature cells embedded within bone, and osteoclasts are the cells responsible for bone resorption.

Osteoblasts are the bone-forming cells that secrete the unmineralized bone matrix, called osteoid. They line the surfaces of growing bone and produce the organic component mostly made of collagen type I and other proteins. This osteoid is later mineralized to become mature bone. Osteoblasts originate from osteogenic (osteoprogenitor) cells, which are mitotically active stem cells found in the periosteum and endosteum; when they divide and differentiate, they become osteoblasts. Once the matrix is laid down, some osteoblasts stay on the surface as lining cells, some become embedded in the matrix and differentiate into osteocytes, and others may contribute to further growth. In contrast, osteocytes are mature cells embedded within bone, and osteoclasts are the cells responsible for bone resorption.