Which cells line flat bone surfaces and help maintain the bone matrix?

Which cells line flat bone surfaces and help maintain the bone matrix?

• A. Osteoblasts
• B. Osteoclasts
• C. Osteocytes
• D. Bone-lining cells

Answer: (D)

Bone-lining cells are flattened osteoblasts that cover bone surfaces where remodeling isn’t actively occurring. They line the periosteal and endosteal surfaces of flat bones and help keep the bone matrix stable by regulating exchange of minerals with the surrounding fluids and by guarding the surface of the bone. If remodeling is needed, these cells can re-activate and become osteoblasts to lay down new matrix. This distinguishes them from osteoblasts, which actively synthesize and secrete the matrix; osteocytes, which reside inside lacunae and coordinate remodeling and response to stress; and osteoclasts, which break down bone tissue.

Bone-lining cells are flattened osteoblasts that cover bone surfaces where remodeling isn’t actively occurring. They line the periosteal and endosteal surfaces of flat bones and help keep the bone matrix stable by regulating exchange of minerals with the surrounding fluids and by guarding the surface of the bone. If remodeling is needed, these cells can re-activate and become osteoblasts to lay down new matrix. This distinguishes them from osteoblasts, which actively synthesize and secrete the matrix; osteocytes, which reside inside lacunae and coordinate remodeling and response to stress; and osteoclasts, which break down bone tissue.