Stem Cells

Outline

The topic of stem cells has become commonplace in our society today. Whether the discussion is of great hopes for future medical breakthroughs or of great ethical dilemmas the subject of stem cells is very timely and relevant. In order to explore the potential impact of stem cells on our society this essay will discuss the following factors:

- What are stem cells?
- Why are stem cells of interest?
- Adult stem cells and how are they harvested?
- What are the advantages of adult stem cells?
- What are the disadvantages of adult stem cells?
- Embryonic stem cells and how are they harvested?
- What are the advantages of embryonic stem cells?
- What are the disadvantages of embryonic stem cells?
- Discussion and Conclusion

What are stem cells?

Stem cells may be defined as a cell that maintains the capacity for unlimited cell divisions (Partridge 133). It is important for mammalian cells to maintain appropriate control over a cell's ability to divide (Chen and Goldhamer 1). Uninhibited cell division is characteristic of disease states such as cancer (Rasmussen 1). In contrast, inadequate cell division is seen in degenerative diseases such as muscular dystrophy (Lefaucher and Sebille 121). Mammalian cells control the capacity to divide by a structural mechanism located on the end of each chromosome, called the telomere (Renault et al 1514). With each cell division some of the deoxyribonucleic acid (DNA) at the ends of the telomeres is lost (Li 671). Once the telomeres reduce to a certain length, following the loss of some of the DNA at the telomere ends with each cell division the cell permanently loses the ability to divide (Li 671). This cell is then termed quiescent and is characteristic of a mature or terminally differentiated cell (Spradling 133). Terminally differentiated cells make up more than ninety percent of an adult body (Reyes et al 338). Once damaged a terminally differentiated cell does not have the ability to renew itself and follows the usual fate of cell death (Thomas and Vanderhyden 1).

Stem cells contain an active enzyme that ensure that the DNA lost at the ends of the telomeres with a cell division are replaced (Spradling 134). With the continual replacement of the telomere ends the stem cell maintains the unlimited ability to continue to divide.

Why are stem cells of interest?

With the capacity for unlimited cell division stem cells are able to renew and repopulate cells within a

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