Bones are living tissue that constantly rebuilds itself throughout your entire life.

The longer version

Bone tissue contains several cell types working at once, which is what makes it living rather than inert. Some cells dissolve old or damaged material, while others lay down fresh mineral-rich matrix in its place. This turnover lets skeleton repair tiny cracks from everyday loading and also lets it change shape slightly in response to repeated stress. Blood vessels run through the hard outer layer, delivering the raw materials and carrying waste away.

Because the process never fully stops, the skeleton you have years from now is not made of exactly the same material as the one you have today, even though the overall shape stays recognisable.

Where this entry sits

These facts look at how the human body works in ordinary moments, from breathing and blinking to balance and sleep. They focus on anatomy, senses, and small reactions that happen constantly without any conscious effort. The full list sits on the Human Body page, where every entry is listed in order.