Stem Cells

There are two kinds of stem cell: embryonic and adult. Both kinds can either divide to produce another stem cell like themselves...or produce a more specialized cell.

Embryonic stem cells (from embryos) are truly pluripotent, meaning that they have the potential to develop into any kind of cell.
Adults tissues have stem cells as well. These cells tend to be less plastic, meaning that they can't differentiate into the variety of cells that embryonic stem cells can. They serve the purpose of replenishing lost cells (like skin or blood) .

Bone marrow might come to mind when you think of stem cells, and this is because bone marrow contains stem cells for the creation of new blood cells and is used in the post-chemotherapy treatment of leukemia.

Some adult stem cells, like those found in the umbilical cord, are pluripotent, and this is why you might have heard about "cord blood donations." These cells can differentiate into any kind of cell just like embryonic stem cells.

What can you use stem cells for? Well, think of them the same way you would think of a transplant. You can transplant new cells for a tissue that has lost cells. Wouldn't it be cool to use stem cells and regenerate heart cells that were lost to scarring from a myocardial infarction? Re-growing nerve cells in spinal injuries would also be an exciting new therapy in medicine.

Stem cells could also be used to grow groups of a specific kind of tissue for drug testing.

Want to know more?
LINK: NIH
LINK: How Stuff Works
LINK: Stem Cells in the News