History
A stem cell is a unique type of cell which has the potential to transform into a variety of human cells. For example, it can transform into a muscle, blood, or brain cell. This of course, creates potential to cure diseases but brings up many uncomfortable moral issues.
A Timeline of the History of Stem Cells:
- 1950s: Discovery of the Stem cell in the bone marrow
- 1960s: Discovery of the stem cell in the brain
- 1981: Scientists derive the stem cells of embryos from mice
- 1998: Successful at deriving stem cells from the human and culturing it
- 2006: Induced pluripotent stem cells is introduced
There are two types of stem cells: adult and embryonic stem cells. Each has their own unique properties, limitations and abilities. The embryonic stem cell is the type that causes the most controversy, because as its name implies, it is derived from an embryo.
Adult stem cells, also called limited or somatic, are stem cells which are found in developed organs/tissues of the human body. The most famous places are the bone marrow and the umbilical cord. Adult stem cells are limited in use because they can only be applied to areas from which they originated in. For example, a bone marrow stem cell will only be effective if reinserted in the bone marrow. Another problem with adult stem cells is that they are difficult to detach from the organ and when detached, it is very difficult to cultivate and duplicate in the lab. Adult stem cells cannot grow outside of the body.
Embryonic stem cells, also called unlimited, are derived from the 3 day old embryo. These embryos generally have been donated by fertility clinics, and have been created through vitro or artificial fertilization. Embryonic stem cells are more versatile as they can develop into ANY type of cell under ther right direction. Embryos generally flourish when culured, and have the capability to keep duplicating one year after its separation from the original body. Although the embryonic stem cells hold more potential for a cure, it has created much controversy among america and the world as some view the embryo as much as a human.
Terms to Know:
Specialized Verses Unspecialized: An unspecialized stem cell is one that has not transformed into any type of cell nor hold designs to function as a particular tissue. A specialized cell, such as a blood tissue, carries a specific function only.
Differentiation: the proccess of an unspecialized stem cell turning into a specialized stem cell.
Induced Pluripotent Stem Cells: Adult cells that have been genetically engineered to have characteristics of the embryonic stem cell
Somatic Nuclear Transfer: Also called therapeutic cloning, this proccess is when the nucleus of an unfertilized egg cell is removed and replaced with the nucleus of the desired cell the experimenters want to form. Is allowed under supervision to duplicate.
