Bones are the structures that comprise our skeletal system. The skeletal system is the body's internal supporting structure.

Bones are living tissue. This means that they contain living bone cells, blood vessels and nerve cells. 

Bones can feel pain. If a bone breaks, this pain will be excruciating. When this happens, a doctor must place the broken ends of the bone back together. A cast can be placed over the broken bone to make sure that the ends of the bone stay in place. 

In a couple of weeks, the bone cells will gradually duplicate. When this happens, the ends of the bone grow back together, and the bone heals. 

The ends of bones contain cartilage. Blood vessels transport energy and oxygen to the bone cells.

Nerve cells transmit information in and out of the bone. The central part of a bone consists of bone marrow. New blood cells are produced in the marrows of certain bones. 

The space between bone cells is mostly comprised of calcium-rich medial substance. Our bones need calcium to stay healthy. Calcium can be gained by eating milk products, for example. To transmit calcium to the bones, we also need plenty of vitamin D.