Stem Cells

INTRODUCTION
An objective of science is to improve people´s life, an important way to do it, is creating and developing new resources to improve people´s health. Through human history diseases and devastating illnesses have been affecting us; science tries to understand them and eliminate them. A very effective way science has develop its knowledge is researching our own conducts and biologicalprocess, also every living organism as plants and animals for example from them we have discover the capability of regenerate missing parts of their bodies. Even though we cannot do that with legs, arms or fingers, we do not think that our bodies are constantly regenerating blood, skin and other tissues; this is a very important process on human development. As part of this self investigationscientists have discovered stem cells. First discovered in the 1950s in experiments with bone marrow were the existence of this cells were established as part of our bodies and led the development of bone marrow transplantation now used as therapy technique in medicine. Scientists discovered that the cells of the embryo were capable to produce every cell type in the human body, after this they wereable to extract embryonic stem cells from mice in the 1980s that were discovery of bona fide stem cells from mice occurred in 1971 but it was until 1998 that it was possible to keep them alive the laboratory.
Stem cells are also important as a tool on the study for better understanding of the basic biology of human. Like the regenerative or reparative medicine in which scientists research the useof stem cells for the possibility to apply therapies to treat diseases with healthy cells replacing damage cells in adult organisms.
But what are stem cells?
An specific definition refers the stem cells as “precursor cells that can give rise to multiple tissue types” it can be refer that stem cells are the primary cells in the body, to make clear this definition I have to explain that to createa new organism it is needed the union of an egg and sperm to produce a fertilized egg, after that, the production of stem cells begin, these cells are going to bring on specialized and differentiated cells that carry out the specific functions of the body.


These cells have two important characteristics that differs them from other types of cells. The first is that theyare unspecialized cells that renew themselves for long periods through cell division. And the second is that under certain physiologic or experimental conditions, they can be induced to become cells with special functions. They also can follow different paths and there a lot of functions in the organism they can contribute to.

There are many different kinds of stem cells. The first divisionis based on the main function, there are: Totipotent stem cells, which can give rise to a fully functional organism as well as to every cell type of the body. Also there are pluripotent stem cells that are capable of giving rise to virtually any tissue type, but not to a functioning organism. Another kind is multipotent stem cells this ones are more differentiated cells and they can give rise onlyto a limited number of tissues.
Other division is based on the stage of the human develop these are: Embryonic stem cells, which are found on the early stage on human development, in the 3 to 5 day old embryo, called blastocyst, stem cells in developing tissues give rise to the multiple specialized cell types that make up the heart, lung, skin, and other tissues. The other kind is Adult stemcells which are found on tissues of fully development humans, these ones are considered less flexible than embryonic stem cells due to they have the potential to produce every cell type in the human body.

The importance of these cells comes out with the idea from the scientists to treat diseases such Cancer, Parkinson´s disease, heart disease, diabetes and some other ones, with stem cells, they...