STEM CELLS

INTRODUCTION

-         Stem cells are undifferentiated cells of a multicellular
       organism.

                                      

-         These cells can differentiate into many types of cells.

-         These cells also have the ability of self renewal.

Types based on ability to differentiate: -

-         Totipotent: - These stem cells can differentiate into all
                            cell types.

                                       

-         Pluripotent: - These stem cells can differentiate into
                             many cells but not all cells.

-         Multipotent: - These stem cells can differentiate into
                               some cells but not many.

-         Unipotent: - These stem cells can differentiate into only
                             one type of cell.

Types based on origin: -

-         Embryonic stem cells

o   These are derived from the inner mass of the blastocyst.

o   Blastocyst is that stage of an embryo when it is 4-8 cells old.

                                 

o   These are Pluripotent and can differentiate into almost 2000 types of cells.

o   These are used in regenerative medicine and artificial organs.

 Adult stem cells

o   These are found in developed organism.

o   These have twin properties of self renewal and differentiation.

o   These orient from the bone marrow.

o   These are Multipotent and help in regeneration of some organs like skin.