Coax embryonic stem cells into a variety of adult cell types in our Virtual Stem Cell Laboratory. Try it yourself Coax embryonic stem cells into a variety of adult cell types in our Virtual Stem Cell Laboratory. Twitter Stumbleupon Delicious Digg. Children's Hospital Boston.
Stem cells originate from two main sources : adult body tissues and embryos. The body can use these stem cells whenever it needs them. Also called tissue-specific or somatic stem cells, adult stem cells exist throughout the body from the time an embryo develops. The cells are in a non-specific state, but they are more specialized than embryonic stem cells. They remain in this state until the body needs them for a specific purpose, say, as skin or muscle cells.
Day-to-day living means the body is constantly renewing its tissues. In some parts of the body, such as the gut and bone marrow , stem cells regularly divide to produce new body tissues for maintenance and repair. Stem cells are present inside different types of tissue. Scientists have found stem cells in tissues, including:. However, stem cells can be difficult to find. They can stay non-dividing and non-specific for years until the body summons them to repair or grow new tissue.
Adult stem cells can divide or self-renew indefinitely. This means they can generate various cell types from the originating organ or even regenerate the original organ, entirely.
This division and regeneration are how a skin wound heals, or how an organ such as the liver, for example, can repair itself after damage. In the past, scientists believed adult stem cells could only differentiate based on their tissue of origin. However, some evidence now suggests that they can differentiate to become other cell types, as well.
Around 3—5 days after a sperm fertilizes an egg, the embryo takes the form of a blastocyst or ball of cells. The blastocyst contains stem cells and will later implant in the womb. Embryonic stem cells come from a blastocyst that is 4—5 days old. When scientists take stem cells from embryos, these are usually extra embryos that result from in vitro fertilization IVF. In IVF clinics, the doctors fertilize several eggs in a test tube, to ensure that at least one survives. They will then implant a limited number of eggs to start a pregnancy.
This single-celled zygote then starts to divide, forming 2, 4, 8, 16 cells, and so on. Now it is an embryo. Soon, and before the embryo implants in the uterus, this mass of around — cells is the blastocyst.
The blastocyst consists of two parts:. The inner cell mass is where embryonic stem cells are found. Scientists call these totipotent cells. The term totipotent refer to the fact that they have total potential to develop into any cell in the body. With the right stimulation, the cells can become blood cells, skin cells, and all the other cell types that a body needs. In early pregnancy, the blastocyst stage continues for about 5 days before the embryo implants in the uterus, or womb.
At this stage, stem cells begin to differentiate. Scientists have used MSCs to create new body tissues, such as bone, cartilage, and fat cells. They may one day play a role in solving a wide range of health problems. Scientists create these in a lab, using skin cells and other tissue-specific cells.
This fundamental research using mice may inform According to the researchers, the gene regulator Id If extended to humans, this technique could greatly improve patients' quality of According to a new study, dental epithelial stem cells from mice can generate mammary ducts and Using a novel technique, researchers have been able What Makes Us Human?
Stem cell researchers have now found a previously overlooked The researchers hypothesize that a lower channel density may have The results illuminate one of the These are adult stem cells that have been changed in a lab to be more like embryonic stem cells. Scientists first reported that human stem cells could be changed in this way in Induced pluripotent stem cells don't seem to be different from embryonic stem cells, but scientists have not yet found one that can develop every kind of cell and tissue.
The only stem cells now used to treat disease are hematopoietic stem cells. These are the blood cell-forming adult stem cells found in bone marrow. Every type of blood cell in the bone marrow starts as a stem cell. Stem cells are immature cells that are able to make other blood cells that mature and function as needed. These cells are used in procedures such as bone marrow transplants.
These help people with cancer make new blood cells after their own hematopoietic stem cells have been killed by radiation therapy and chemotherapy. They may also be used to treat people with conditions such as Fanconi anemia. This is a blood disorder that causes the body's bone marrow to fail.
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