Question: What repairs cuts, bruises and broken bones?

Ruth Elderfield answered on 18 Jun 2015:

When we first get a cut or our bone brakes our blood clots when flat red cells (platelets) clump together to act as a plug, these are strengthened by a fibrin net, this becomes a scab. Our body sends in the immune system to kill off any invaders. This can cause swelling and heat (inflammation).
Below the scab specialist cells move in (fibroblasts) that provide the building blocks for the new blood vessels (capillaries). In the skin surrounding skin cells stretch over the cut to cover the wound. Eventually the scab falls off.
In the bones, tissue and a tougher material called collagen fill in the break, over the next few weeks this will be strengthened by minerals forming a hard strong replacement bone.