A stem cell is a remarkable cell, as it has the amazing ability to change into a variety of different cell types in the body such as heart muscle cells, brain cells, and skin cells. Stem cells, which are often referred to as one of the body's "master cells," can grow into any one of the body's more than 200 cell types. Stem cells assist the body in maintaining, renewing and repairing tissue and cells damaged by disease, injury and everyday life. If you think about it, stem cells act as the internal repair system for the body.
The magic begins when a stem cell divides. Each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function such as a muscle cell, a red blood cell, or a brain cell. Stem cells also have the capability to self-renew, meaning they can reproduce themselves many times over.
Stem cells can create additional cells and may later be transplanted or used for a variety of medical procedures. This is why stem cells are collected and stored.
Umbilical cord blood and bone marrow are two sources of stem cells that may sound familiar to people. Both umbilical cord blood and bone marrow contain a type of adult stem cell. Adult stem cells, which come from the tissue of live human beings, are currently the only type of stem cell commonly used to treat human diseases. Now, with cord blood banking, stem cells can be properly preserved if and when they are ever needed. Read about other sources of adult stem cells.
Embryonic stem cells come from human embryos that are a few days old. Cells from these embryos can be used to create stem cell "lines"- cell cultures that can be grown indefinitely in the laboratory. Embryonic stem cell research can sometimes be considered controversial. Unlike adult stem cells (such as those from umbilical cord blood); embryonic stem cells are not currently used as treatment options for people.