Compact bone. Light micrograph of a section through human compact bone. This tissue forms concentric layers (lamellae, orange) around Haversian canals (white). The canals contain blood, lymph vessels and nerves. The lamellae and canals together form a Haversian system. Many systems are arranged in columns running parallel to the long axis of the bone. Osteocytes (small brown ovals), the cells responsible for the maintenance of the bony matrix, are housed in spaces known as lacunae. Projections of their cytoplasm are held in tiny channels called canaliculi (fine brown lines). Aniline-picric acid stain. Magnification: x45 at 35mm size.