Final answer:
The inner portion of the periosteum contains osteoblasts and is critical in bone growth, repair, and providing a site for tendons and ligaments to attach. It is also rich in vessels that nourish the bone.
Step-by-step explanation:
The periosteum is a fibrous membrane that covers and protects the outer surface of bones, except at the joints. In its inner portion, the periosteum contains a layer that includes osteoblasts, which are cells responsible for bone formation. These osteoblasts contribute to the growth and healing of bones by producing an unmineralized bone matrix called osteoid, which eventually leads to the development of new bone tissue. Additionally, the periosteum is rich in blood vessels, nerves, and lymphatic vessels that provide essential nutrients and signals to maintain bone health. Ligaments and tendons also attach to bones via the periosteum, allowing for the transfer of forces to the skeletal system during movement.