Stem cell

Stem cells are unspecialized cells which have a remarkable ability to differentiate to any type of body cells during early life and growth. There are two main types of stem cell; pluripotent embryonic stem cells (ESC's) derived from the inner cell mass of the blastocyst and adult stem cells which are found in differentiated tissues throughout the body and their role is to maintain and repair tissue cells.

Stem Cell Information, The national institutes of health resource for stem cell research. http://stemcells.nih.gov/