Function: support, protection, storage site of calcium and phosphate.
Origin: mesoderm: somites, mesenhyme.
Location: skeletal system: long, short, flat and irregular bones.
Composition: proteoglicans, noncollagenous glycoproteins, hydroxyapatite crystals (calcium phosphate)
Location: parallel orientation in lamellar bone: osteons (Haversian system), interstitional lamellar, circumferential lamellar.
Function: proliferation and differentiation into osteoblasts, nutritional support of the osteocytes, bone repair.
Location: innermost layer of periosteum and endosteum in marrow cavities, osteonal (Haversian) canals and perforating (Volkmann's) canals
Function: secretion and mineralization of extracellular matrix: ground substance and collagen fibers, physiological and repair regeneration.
Location: initial nonmineralized bone - osteoid, periosteum, endosteum.
Function: mature bone cells, differentiated osteoblasts, maintenance of bone matrix by secretion and resorption.
Location: lacunae in extracellular matrix.
Function: bone resorption, phagocytosis, bone remodelling.
Location: bone surface.
Origin: mesenhyme, bone marrow, blood monocytes, mononuclear phagocytic system.
Function: support, protection, and storage site of calcium and phosphate.
Location: skeleton of the developing fetus
Composition: ground substance, thick collagen fibers in interlacing arrangement, randomly arranged abundant cells.