An osteon or Haversian system is composed of?

An osteon is a long cylindrical tube shaped unit in mature compact bone. It consists of concentric layers of bone lamellae surrounding a central canal also known as the Haversian system. They are oriented parallel to the long axis of the bone and to the main compression stresses. Structurally a group of concentric tubes resembling rings of a tree trunk. Each tube is a lamellae( little plate); a layer of bone matrix which collagen fibers and mineral crystals line up and run in opposite direction. This pattern alternates to withstand torsion, twisting and stresses and inhibits crack propagation.
Through the core of the osteon runs the Haversian canal also known as central canal and like all bone cavities it is lined with endosteum. It has its own blood vessels that supply nutrients to the bone cells of the osteon and its own fibers.