Stem cells are cells that have the potential to become many different cell types or specialized. Stem cells can be regarded as primitive, "non-specialized cells" that are capable of dividing and become specialized cells such as liver cells, muscle cells, blood cells and other cells with specific functions. Stem cells are called "undifferentiated" cells, which are not yet engaged in a development path that is an organ or tissue specific. The process of change in a particular cell type is called differentiation. In some parts of the body, stem split cells periodically to renew and repair the existing urban fabric. Bone marrow and gastrointestinal tract are examples of areas where stem cells under renovation and repair of tissues.
What is stem cells?
Stem cells are cells that have the potential to become many different cell types or specialized. Stem cells can be regarded as primitive, “non-specialized cells” that are capable of dividing and become specialized cells such as liver cells, muscle cells, blood cells and other cells with specific functions. Stem cells are called “undifferentiated” cells, which are not yet engaged in a development path that is an organ or tissue specific. The process of change in a particular cell type is called differentiation. In some parts of the body, stem split cells periodically to renew and repair the existing urban fabric. Bone marrow and gastrointestinal tract are examples of areas where stem cells under renovation and repair of tissues.
The best example to understand and easier for human stem cell is a fertilized egg or zygote. A zygote is a cell formed by the union of a sperm and egg. Sperm and egg each carries half the genetic material necessary to form a new individual. When the cell or the zygote begins to divide, which is known as a fetus. One cell becomes two, two becomes four, four becomes eight, eight to sixteen and so on, doubling quickly to finish the whole body creates sophisticated. This body is a person a very complex structure, consisting of thousands of millions, many cellular functions as diverse as those of your eyes, your heart, your immune system, the color of skin, brain, etc. All specialists cells make up the organ systems are descendants of the original zygote, a stem cell with the potential to eventually develop all types of cells in the body. Zygote cells are totipotent, ie have the capacity to become any cell in the body.
The process by which stem cells are committed to differentiate or specialized cells is complex and involves regulation of gene expression. Research continues to better understand the molecular events and the controls needed for stem cells to become specialized cell types.
Why stem cells are cells important?
Stem cells represent an exciting area of medicine because of their potential to regenerate and repair damaged tissues. Some current treatments such as bone marrow transplantation and the use of stem cells and their potential to regenerate damaged tissue. Other treatments are being evaluated for transplantation of stem cells in a body part injured and leadership to grow and differentiate into normal tissues.
Embryonic stem cells
During the early stages of embryonic development are relatively undifferentiated cells (immature) and seems to be able to develop or differentiate, in almost all tissues in the body. For example, stem cells from one part of an embryo that can become part of the eye may be transferred to another part of the embryo and can become blood cells, muscles, nerves and liver.
The cells are totipotent early state (see above) and can distinguish any cell type in the body. After about seven days, the zygote forms a structure called a blastocyst, which contains a mass of cells that eventually becomes the fetus and trophoblastic tissue that eventually becomes the placenta. If you take cells from the blastocyst at this stage are called pluripotent, meaning they have the ability to become many types of human cells. The cells at this stage is often called a blastocyst embryonic stem cells do. When all types of embryonic stem cells grown in the laboratory, which can divide and grow indefinitely. These cells are called embryonic stem cells.
Fetal stem cells
The embryo is called a fetus after the eighth week of development. Embryo contains stem cells that are pluripotent and, finally, the various tissues in the body of the fetus.
Adult stem cells
Adult stem cells are found in all humans in small quantities. Adult stem cells are a type of cells that were able to handle very efficiently in bone marrow transplantation during the past 30 years. This is the stem cells that are largely site-specific tissues. More often gives rise to all body cells, these cells can give rise only a few types of cells are specific tissues or organs. So called pluripotent stem cells. Adult stem cells are sometimes referred to as somatic stem cells.
The best characterized example of an adult stem cell is a blood stem cell (hematopoietic stem cells). When we refer to a bone marrow transplant, a stem cell transplant or a blood transplant, the cells are transplanted stem cells are hematopoietic or blood stem cells. This cell is a very rare mainly found in adult bone marrow.
One of the most important discoveries in recent years has been the reversal of a long-standing belief that scientists an adult stem cell a stem cell has been fully committed. Previously it was believed that hematopoietic stem cells or the formation of blood can cause other blood cells, and could never be another type of stem cells. Now it is clear that some of these adults apparently committed stem cells are cells capable of changing direction to become a stem cell in another body. For example, some models of bone marrow transplantation in rats with liver damage in liver cells partially re-growth from the transplanted bone marrow. Similar investigations can be done to show that many different cell types can be derived from each other. It appears that cardiac cells can be collected from bone marrow, the bone marrow cells grown from stem cells derived from muscle stem cells and brain can develop into many cell types.
peripheral blood stem cells
Most blood stem cells are present in bone marrow, but some are present in the blood. This means that the so-called peripheral blood stem cells (PBMCs) can be isolated from a blood sample. Blood stem cells can give rise to a large number of very different cells that make blood and immune system, such as red cells, platelets, granulocytes and lymphocytes.
* Red blood cells carry oxygen around the body and gives blood its color.
Platelets are cell fragments * that prevents a person from bleeding and help the body heal from the coagulation and cutting.
* Granulocytes are a type of white blood cells that fight bacterial infections.
* Lymphocytes are a type of white blood cells that are part of the immune system, helps fight infection and may also be involved in protection against cancer.
All these cells are very different with very different functions from a common ancestor committed blood-forming (hematopoietic) stem cells.
Umbilical cord stem cells
Umbilical cord blood contains stem cells that are genetically identical to the newborn. As adult stem cells, multi-potent stem cells are able to distinguish some but not all, cell types. Therefore, it is often in umbilical cord blood banks, or stored for possible future use if the person needs to stem cell therapy.
Induced pluripotent stem cells
Induced pluripotent stem cells (ICM) has been established for human cells in 2007. These are adult cells that are genetically is a state of embryonic stem-like cells. In animal studies, iPS cells appear to have characteristics of pluripotent stem cells. Human iPS cells can differentiate into several types of fetal cells. Confederation is invaluable in studying disease progression and treatment, and may have future use in transplantation medicine. More research is needed on the development and use of these cells.