Bones are composed of cortical bone and trabecular bone. Cortical bone is tough and strong, and trabecular bone is less dense than cortical bone and lighter. Bones are also composed of bone-forming cells, collagen, proteins, inorganic mineral salts and bone resorbing cells.
Bones provide protection for the organs and provide support for the body. The adult skeleton contains 206 different bones. There are two types of bones that can be identified by the way the collagen forms. Woven bone is identified by unorganized collagen fibers and is weak. Lamellar bone is identified by organized, parallel collagen fibers and is strong.