| Figure 12: The molecular arrangement of collagen and hydroxyapatite crystals in compact bone. (a) Collagen fibers overlap adjacent fibers as they repeat every 680 Å. Hole zones are areas of low density bone collagen and overlap zones are areas of very high density bone collagen. (b) Hydroxyapatite crystals (Ca10[PO4]6[OH]2) are arranged in layers within each fiber, resenbling overlapping bricks (1 Å = 10-8 cm). | |