<Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> Stem cells are biological cells that can differentiate into other types of cells and can divide to produce more of the same type of stem cells . They are found in multicellular organisms . </P> <P> In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues . In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues . In a developing embryo, stem cells can differentiate into all the specialized cells--ectoderm, endoderm and mesoderm (see induced pluripotent stem cells)--but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues . </P> <P> There are three known accessible sources of autologous adult stem cells in humans: </P>

Where are stem cells made in the body