What is the connective tissue that covers bone?

The connective tissue that covers bone is called the periosteum. It is a tough, fibrous membrane that surrounds and protects the bone. The periosteum is composed of two layers: an outer fibrous layer and an inner cellular layer. The fibrous layer is made up of collagen fibers, which provide strength and support to the bone. The cellular layer is made up of osteoblasts, which are cells that build new bone, and osteoclasts, which are cells that break down old bone. The periosteum also contains blood vessels and nerves, which supply the bone with nutrients and oxygen.