Stem Cells

Each cell in your body has a specific shape and a specific job to do - we say they are specialised. This all happened whilst you were an embryo and specialized cells cannot later change to become a different type - muscles cells will always be muscle cells; epithelial cells will always be epithelial cells and so on, although cutting-edge research now suggests that this may not be the case.

But there are some cells which are unspecialised - these are called stem cells and they have the ability to become any type of cell. When they were discovered, there was a lot of excitement in the medical community because using stem cells could lead to some incredible treatments. Scientists researching them believe that they could possibly be used to repair damaged organs in the body like bones, cartilage and the heart. They could also be used to treat brain diseases like Parkinson's, to reverse paralysis or even regrow lost limbs. But it will be a long time until medical science reaches that stage; a lot of research is needed to find out how stem cells work, how to make them do what we want and to make sure that they will not just grow uncontrollably in the body. Human stem cells can be obtained from adult bone marrow or from growing embryos.

A big issue surrounding stem cells is therapeutic cloning. This is a theoretical process where you are cloned to produce an embryo. Stem cells are then extracted from this embryo and grown to produce the organ that you need. There would be no problem with your body rejecting the new tissues as they would be from your own cells anyway. For an exam, you could be asked to weigh up the pros and cons of therapeutic cloning and the use of stem cells, for example, one issue is, that during the process, some embryos could be destroyed. You will need to present your arguments using the scientific ideas that you have learned surrounding stem cells.

Stem cells could help us to repair damaged body parts. They might also be used in the treatment of previously incurable diseases. But is it ethical to use them? Try this quiz to refresh your knowledge of stem cells.