Stem cells are always regarded as cells with unique and extraordinary
properties. SCs are able to self-renew and differentiate into specialized cells and this is
a great advantage to maintain homeostasis in the body. The cells can divide with two
different strategies and they are influenced by intrinsic and extrinsic factors of their
microenvironment in which there are: the niche. The internal signals are represented by
the genetic information of the cells, the external signals come instead from the
microenvironment and they are physical or chemical signals. Stem cells are classified
into embryonic stem cells and adult stem cells. Embryonic stem cells are derived from
the inner cell mass of the blastocyst, these have great potential and over the years
researchers have studied their properties and the importance of keeping them in
appropriate culture conditions. Adult stem cells are found in a large number of tissues
and have the very important role to replace damaged cells in living tissue. SCs can also
be classified according to their potential, so they can be defined as totipotent,
pluripotent, multipotent and they can differentiate respectively in a decreasing number
of specialized cells of the body.
Keywords: Adult stem cells, Division, Embryonic stem cells, Mesenchymal stem
cells, Multipotent stem cells, Niche, Pluripotent stem cells, Stem cells, Totipotent
stem cells.
