What are the functions of the elements of the internal structure of the tubular bone?

Tubular bones have a cavity inside that lightens weight and increases strength. Inside the cavity is a supply of nutrients – yellow bone marrow. Bone heads are formed by intersecting bone plates of cancellous substance, its role is to reduce mass and increase strength. Here is hidden a hematopoietic organ – the red bone marrow.

Outside, the bone is covered with the periosteum, it provides the metabolism of the bone and its growth in thickness. And growth in length is the division of cartilage cells on the heads of bones.