Understanding Stem Cells part 9

When the blastocyst is used for stem cell research, scientists remove the inner cell mass and place these cells in a culture dish with a nutrient-rich liquid where they give rise to embryonic stem cells. Embryonic stem cells seem to be more flexible than stem cells found in adults, because they have the potential to produce every cell type in the human body. They are also generally easier to collect, purify and maintain in the laboratory than adult stem cells.

Understanding Stem Cells part 8

In normal development, the blastocyst would implant in the wall of the uterus to become embryo and continue developing into a mature organism. Its outer cells would begin to differentiate into the progressively more specialized cell types of the body.

Understanding Stem Cells part 7

Embryonic stem cells

A blastocyst (BLAST-oh-sist), is a pre-implantation embryo that develops 5 days after the fertilization of an egg by a sperm. It contains all the material necessary for the development of a complete human being. The blastocyst is a mostly hollow sphere of cells that is smaller that the period at the end of this sentence. In its interior is the inner cell mass, which is composed of 30-34 cells that are referred to by scientists as a pluripotent because they can differentiate into all of the cell types of the body. In common usage, "embryo" can refer to all stages of development from fertilization until a somewhat ill-defined stage when it is called a fetus. Scientists use terms such as "morula" and "blastocyst" to refer ti precise, specific stages of pre-implantation development. In order to be as precise as possible.

Understanding Stem Cells part 6

Stem cells are found in all of us, from the early stages of human developmen tto the end of life. All stem cells may prove useful for medical research, but each of the different types has both promise and limitations. Embryonic stem cells, which can be derived from a very early stage in human development, have the potential to produce all of the body's cell types. Adult stem cells, which are found in certain tissues in fully developed humans, from babies to adults, may be limited to producing only certain types of specialized cells. Recently, scientists have also identified stem cells in umbilical cord blood and the placenta that can give rise to the various types of blood cells.

Understanding Stem Cells part 5

Over the past two decades, scientists have been gradually deciphering the processes by which unspecialized stem cells become the many specialized cell types in the body. Stem cells can regenerate themselves or produce specialized cell types. This property makes stem cells appealing for scientists  seeking to create medical treatments that replace lost or damaged cells.

Understanding Stem Cells part 4

What is a stem cell?

Ultimately, every cell in the human body can be traced back to a fertilized egg that came into existence from the union of egg and sperm. But the body is made up of over 200 different types of cells, not just one. All of these cell types come from a pool of stem cells in the early embryo. During early development, as well as later in life, various types of stem cells give rise to the specialized  or differentiated cells that carry out the specific functions of the body, such as skin, blood, muscle and nerve cells.

Understanding Stem Cells part 3

Stem cells research is being pursued in the hope of achieving major medical breakthroughs. Scientists are striving to create therapies that rebuild or replace damaged cells with tissues grown from stem cells and offer hope to people suffering from cancer, diabetes, cardiovascular disease, spinal-cord injuries and many other disorders. Both adult and embryonic stem cells may also provide a route  for scientists to develop valuable new methods of drug discovery and testing. They are also powerful tools for doing the research that leads to a better understanding of the basic biology of the human body.