What is the difference between embryonic and adult stem cells?
Some organs contain stem cells that persist throughout adult life and contribute to the maintenance and repair of those organs. Not every organ has been shown to contain stem cells, however, and generally adult stem cells have restricted developmental potential, in that their capacity for proliferation is limited and they can give rise only to a few cell types. Embryonic stem cells, by contrast, can divide almost indefinitely and can give rise to every cell type in the body, suggesting that they may be the most versatile source of cells for transplantation therapy.
Embryonic stem cells are stem cells isolated from the inner cell mass of a blastocyst (stage of embryonic development when implantation occurs). Embryonic stem cells are believed to be pluripotent, i.e. have the ability to differentiate into any and all cell types. Adult stem cells are stem cells obtained from a person or from the umbilical cord. Scientists have discovered that some stem cells (adult stem cells) persist after birth. These cells appear to be some kind of back-up cell, prepared to differentiate into a particular cell if and when needed. Most adult stem cells are multipotent and can only form a limited number of cell types.
