Stem cells are unspecialized cells (cells not yet developed towards any particular use) and can renew themselves through cell division. Under specific conditions, they can be induced to develop into cells with special functions, such as muscle cells or the bile producing cells of the liver.
There are basically 2 types of stem cells - adult stem cells and embryonic stem cells. Embryonic stem cells are present in 3-5 day old embryos,and develop into cells which make the lungs, heart, skin and other tissue. Adult stem cells are present in bone marrow and parts of the brain, which replace cells lost through injury or wear and tear.
Stem cells have become one the hottest areas of biological studies due to their immense potential of curing despises such Parkinson's and heart disease. They can also be used to study the effects of toxins and drugs, and also understanding birth defects.
Once stem cells are effectively controlled, countries like India will benefit immensely. Cheap organs and medication will be made available and longer life of these will make them a boon for rural victims of fatal diseases such as cancer and diabetics.
But some hurdles would need to be overcome before we can exploit the full potential of these biological marvels:
1. Scientists would need to understand signals which cause stem cells to develop into specialized cells.
2. We would also need to understand how to control differentiation very accurately, to develop specific cell lines.
3. We would need to deal with facilitating stem cell survival in a donor and the problem of immune rejection.
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