Question: How are bodies able to repair themselves?

Claire Donald answered on 17 Jun 2018:

It is important for your body to heal itself after an injury to prevent an infection. There are different kinds of wounds (like cuts, scrapes or burns) that take varying lengths of time to heal depending on their severity but usually there are 3 stages of repair that happen.
First, nearby blood vessels expand to allow more blood to get to the area which causes it to become red, hot and swollen. Special cells in our blood are needed to clean the area and start repairs, as well as bring essential oxygen and nutrients. White blood cells arrive and kill off any germs (like bacteria) that have already found their way in. These cells will also clean the site of injury by removing dead or dying cells, as well as any debris from the area. Platelet cells in your blood will form a blood clot to reduce blood loss and seal over the wound. This needs to happen quickly so you don’t bleed to death and usually happens minutes after the injury occurs. The blood clots will dry and form a scab, which protects the tissue underneath from germs. At this stage, the wound will become itchy as the action of pulling the skin to close the area stimulates our nerves making us feel the need to scratch.
Once the site is clean, these cells need to leave to allow other cells to start the repair work. This is the second stage and involves rebuilding broken blood vessels and tissue cells. Healthy cells gather at the edges of the wound and copy themselves to fill in the gaps. This stage takes around 3 weeks.
The final stage is strengthening the area. Scars may form which are less flexible and weaker than the surrounding tissue. After a few months these scars can fade as the area becomes as strong as it was before the injury but some scars will be permanent.