Stem Cells and Cell Differentiation

Stem cells

Undifferentiated cells that can divide and develop into specialized cells.

Differentiation

The process by which cells become specialized.

Totipotent stem cells

Stem cells that can differentiate into every type of cell in a given organism, found only in the zygote and early cell divisions.

Pluripotent stem cells

Stem cells that can differentiate into most, but not all, cell types of a given organism.

Multipotent stem cells

Adult stem cells that can differentiate into more than one cell type, but are more limited than pluripotent stem cells.

Unipotent stem cells

Stem cells that can differentiate only into one specific type of cell.

Example of multipotent stem cells

Bone marrow stem cells, which can differentiate into different types of blood cells.

Example of unipotent stem cells

Germ line cells that produce gametes or epidermal stem cells that produce skin cells.

Flexibility of differentiation in mammals

Mammals exhibit a more flexible pattern of differentiation, but adult cells generally become completely differentiated.

Irreversibility of differentiation in animals

In animals, differentiation is irreversible under natural circumstances.