An osteoblast (from the Greek words for "bone" and "to build") is a mononucleate cell that produces osteoid, which is composed mainly of collagen. Bone is constantly beeing reshaped by osteoblasts, which build bone, and osteoclasts, which resorb bone.

Osteoblasts arise when osteoprogenitor cells (mesenchymal cells), which are located near all bony surfaces and within the bone marrow, differentiate under the influence of growth factors, such as fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-β) and other bone morphogenetic proteins (BMPs).

In addition to osteoid, osteoblasts also secrete enzymes that facilitate mineral deposition within osteoid matrices. They are also responsible for regulating the activity of osteoclasts via soluble mediators. Osteoblasts that become trapped in the bone matrix become osteocytes.

ACTIVATED OSTEOBLAST:The cytoplasm appear to be basophilic via normal H&E stain due to presence of large amount of rER A large Golgi apparatus is also present in the centre.The nucleus is spherical and large.

Skeletal system | Connective tissue cells

Osteoblast | Osteoblast | Ostéoblaste | Osteoblast | Osteoblasto | Osteoblast | Osteoblast