Bone matrix is comprised primarily of collagen, which takes the shape of chains in various sizes and dimensions. Bone matrix is created from various collagens, which are the most abundant proteins in the body. Collagen is abundant, strong and stable, which makes it ideal for creating bone as well as cartilage, skin, tendons and tissues throughout the body.
Fully developed bones consist primarily of proteins and minerals, and vary in size, shape and density. Most bones are comprised mostly of minerals, such as calcium and phosphate. The remaining portions of bones are created from water and matrix collagens, which form before bone minerals are deposited. The collagens that comprise bone matrix vary widely, but undergo the process of synthesis before being added to bones. The synthesis process takes place in osteoblasts, which are cells responsible for generating new bone growth. Collagens may exist as long, thin strands or as tightly coiled and compact elements. Fibrils are the most common bone matrix collagens, but other proteins form matrix, too. According to Augusta Technical College, bone matrix contains inorganic and organic components, such as osteoids and proteins. These proteins include fibronectin, osteonectin, osteocalcin, thrombospondin and matrix-gla-protein. Fibronection is abundant and regulates osteoblast differentiation while osteonectin regulates mineralization. Thrombospondin inhibits bone cell precursors while osteocalcin binds calcium. Lastly, matrix-gla-protein prevents mineralization and causes calcified blood vessels.