• Bone Matrix
    • Lattice of collagen and inorganic compounds secreted by osteoblasts  
    • Osteoid
      • Organic portion of matrix
      • Soft but highly ordered matrix
        • Sets framework for subsequent strengthening by mineralization
      • Made up of proteins and collagen 
    • Hydroxyapatite crystals
      • Inorganic portion of matrix
      • Strong mineralized portion
      • Made of calcium and phosphate
        • Main repository of calcium in the body