Stem cells are undifferentiated or partially differentiated cells in the body and they also have the ability to self-replicate. Stem cells have the potential to give rise to other types of cells.
Undifferentiated Cells: Cells in the body that are not specialized in any specific type to play a specific role in the body are undifferentiated cells. These cells are able to divide in various cell types in the body.
Self Replicating: Stem cells are able to divide and make copies of same cell type.
The function of Stem Cells: The main function of stem cells is to differentiate and provide various types of cells to the body as it grows in the embryo. In living organisms function of stem cells is to repair the damaged body parts by providing cells of the same type as of damaged body tissue.
Potency or Potential of Stem Cells: Potency of stem cells means that how many different types of cells a stem cell can differentiate into. Some cells can differentiate into any cell type of body while others can differentiate into two or one cell type only.
Depending upon the potential of stem cells, they can be classified into different groups
Totipotent Stem Cells: Totipotent are also known as Omnipotent stem cells. These cells are produced by fusion of gamete cells(fertilisation). These cells can give rise to whole organisms. Cells formed after first division of fertilised egg are also called totipotential stem cells. These cells have capacity to self replicate.
Pluripotent Stem cells: These cells are descendant from totipotent stem cells. Pluripotent stem cells can divide into nearly all cell type. These cells are derived form all three germ layers. Pluripotent stem cells are capable of self replicating.
Multipotent Stem Cell: These cells are derived from pluripotent stem cells and these cells can differentiate into number of cell types. These cells divide into cells which are of closely related family. Hematopoietic stem cells are example of multi-potent stem cells
Oligopotent Stem Cells: Oligopotent stem cells are descendant of multi-potent stem cells. These stem cells can differentiate only few cell type. Stems cells like myeloid and lymphoid stem cells are called oligopotent stem cell. These cells are also able for self renewal.
Unipotent Stem Cells: Unipotent stem cells can differenciate into only one type of stem cell. What make these cell different from non-stem cell is that, they can self replicate while other specilized cell in the body cannot renew themself or cannot make copies of themself.
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