1. At the top, the structural parts of the long bone are labeled. They are:
   1. Yellow bone marrow
   2. Periosteum
   3. Compact bone
   4. Spongy bone
   5. Growth plate
2. A portion of the long bone is enlarged below to show the structural parts clearly. The different structures labeled are:
   1. Haversian canals
   2. Osteocyte
   3. Periosteum
   4. Blood vessels
   5. Compact bone
   6. Spongy bone

Haversian canals: These canals contain blood vessels and nerves. Osteoclasts and osteoblasts line the canals. Compact bones: Dense compact bone, found under the periosteum, contains networks of tubes through which blood vessels and nerves travel. Spongy Bones: The tiny structures of spongy bone are arranged in such a way that they can support a lot of force. Red bone marrow is found in the spaces of spongy bone. Growth Plate: Growth plates contain dividing cartilage cells that increase the size of a bone until a person reaches his or her adult height.