Embryonic+Stem+Cells

**Embryonic Stem Cells**

media type="custom" key="6364405" align="left" =I. What are Embryonic Stem Cells? =

Embryonic stem cells are derived from embryos. Specifically, these pluripotent stem cells are obtained from the inner cell mass of a blastocyst. A blastocyst is a hollow microscopic ball of cells, or an early stage embryo after five days of fertilization that usually consist of 150 cells or above. These are suitable because in this early developmental stage, they retain the flexibility to become any of the more than 200 cell types that make up the body.

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**II. Qualities of Embryonic Stem Cells**
Most of these stem cells are derived from donated embryos that develop from eggs that have been fertilized in vitro fertilization clinics. So, these stem cells are not fertilized in a human body.  [|CLICK HERE FOR EMBRYONIC CELL ANIMATION]

These embryonic stem cells are pluripotent and can renew themselves indefinitely. To be pluripotent means that they are able to differentiate into all derivatives of the three primary germ layers. This characteristic distinguishes embryonic from adult stem cells. Embryonic stem cells can generate all cell types in the body while adult stem cells are multipotent and can only produce a limited number of cell types. Thus, the embryonic stem cells are pluripotent and can regenerate indefinitely. Because of these qualities, ES cells have been proposed to help regenerative medicine and tissue replacement. This process is called to cell culture. The embryonic stem cells spread over the surface of a culture dish by isolating the inner cell mass in a culture medium (a nutrient).

If the plated inner cell mass survive, divide, and multiply, they are then removed and placed into new culture dishes. This is repeated for many months in a process called subculturing. Thus millions of embryonic stem cells are obtained. If these cells have proliferated in cell culture for six or more months without differentiating, they are pluripotent. Cells start to differentiate if they are allowed to clump together to form embyoid bodies. Thus, muscle cells, nerve cells, etc are formed.

Scientists try to control the differentiation of embryonic stem cells to generate cultures of specific types of cells. They can change the culture medium or the surface of the culture dish or insert specific genes. There are many formulas to direct the differentiation of these cells called the NIH stem cell report.

=III. Characteristics = There six are characteristics to identify the properties of embryonic stem cells.


 * Growing and subculturing the stem cells for many months ensures the cell is capable of long term growth and self renewal.
 * The presence of transcription factors by undifferentiated cells have to be determined.
 * Have to find different cell surface markers produced by undifferentiated cells.
 * There can't be genetic mutations.
 * The cells can be regrown after freezing.
 * Tests to see if the cells are pluripotent.
 * The cells have to differentiate spontaneously in cell culture.
 * <span style="color: #800080; font-family: Georgia,serif;">Manipulating cells so they will differentiate to form the three germ layers.
 * <span style="color: #800080; font-family: Georgia,serif;">Also, by injecting cells into a mouse to test for the formation of a tumor called a Teratoma can allow scientists to observe the growth and differentiation of the human stem cells.



= = = = = = = = = = = = = = = = =<span style="color: #000000; font-family: Georgia,serif;">IV.Uses and Conclusion = = = <span style="color: #060674; font-family: Georgia,serif;"> The results of differentiated embryonic stem cells into specific cell types by directing the differentiation may be able to treat certain diseases in the future. Some of these diseases are Parkinson's disease, diabetes, vision or hearing loss, or heart disease. Basically, embryonic stem cells can cure diseases that harm organs or tissues that cannot self-repair.

Given the right combination of signals, embryonic stem cells will develop into mature cells that can perform any function and because ESC are able to remain in an undifferentiated state and to divide indefinitely, there are en unlimited number of identical cells.

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