• Question: How are bodies able to repair themselves?

    Asked by Júlia to Eoin, Ester, Ildiko, Natasha, Paul, Tom on 6 Nov 2017.
    • Photo: Eoin McKinney

      Eoin McKinney answered on 6 Nov 2017:

      Our bodies are incredible. Much of what medicine does is just support our bodies ability to get better by itself – antibiotics often just slow down bacteria, for example, helping our immune system to finish the job. Repair usually relies on a fairly small set of cells (called ‘stem’ cells) that don’t ever turn into anything, but instead retain the ability to become any tissue thats needed. Some stem cells can turn into any cell in your body, from skin, brain, heart or muscle. Thats pretty useful when old or damaged cells stop working but it has to be controlled carefully by the body or we could get too much of one cell type when we don’t want it (thats essentially what cancer is).

    • Photo: Ester Gil Vazquez

      Ester Gil Vazquez answered on 6 Nov 2017:

      Out bodies are able to repair themselves because we have adult stem cells. I think the concept of stem cell is a little bit ambiguous and that is because we use it to refer to many different things. So let’s take it from the beginning.
      Our whole body comes from one single cell that divided many many times (while we were still inside mum’s tummy). This cell was, as scientist call it, a totipotent stem cell. Totipotent means that these cell could divide to give rise to all the different parts of our body: from the heart to the skin. However, as cells divide and divide, they loose this capability and, once we are adults, we only have stem cells able to give rise to specific parts of the body – adult stem cells. For example, cells at the surface of the skin are falling continuously and they are replaced by new cells. These new cells come from a pool of stem cells that are in the inner layers of the skin and that can give rise only to skin cells, but not to cells from the heart, bone or eye.When we cut ourselves, for example, it is this pool of cells that reconstructs the damaged skin.
      There are similar pools in other organs like the gut and certain areas of the brain. However, when these cells are missing or when the wound is to big, the body needs to substitute the original tissue by what it is available and that’s when we get scars.

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