Human bones contain bone cells which are constantly in need of nutrients, building materials and oxygen.

Blood vessels that supply calcium and other essential substances pass through the bones.

Bones also feel pain. For example, when you hit something on your tibia or when your bone is damaged, you will feel intense pain. The nerves found in our skeletal system carry messages to and from the brain.

The picture on the right displays the porous, spongy structure of a bone. There is enough space between the calcium- and phosphate-containing parts of the bone to accommodate bone cells, nerves and blood vessels.