In this chapter you will learn about the characteristics of bone tissue, a specialised connective tissue that forms bones. The tissue can give rise to different bone structures distinguishable with the naked eye, and different microscopic organisations of the tissue can also be distinguished. In addition, bones are often lined by a connective tissue called periosteum. You will study that the bone matrix is made up of organic components (type I collagen, glycosaminoglycans, proteins) and inorganic components (hydroxyapatite). Several cell types can be found, some of mesenchymal origin and others of blood origin.