An apple a day

摘要

Stem cells are unprogrammed cells with two defining properties: the capacity to replenish themselves through self-renewal and the ability to differentiate into cells with specific functions. Stem cells play a central role in the development of a new organism and in the repair and regeneration of tissues. A new organism is formed by embryonic stem cells. They are pluripotent, which indicates that they can differentiate into all cell types of the body. Tissue repair and regeneration is the job of adult stem cells. They are more restricted and are normally only able to differentiate into the different cell types of the tissue in which they are found.