Stem cells are undifferentiated cells found in body having capability to develop into different types of cells in the body. Whenever there is a cell division of stem cells, each stem cell has the ability to remain a stem cell or become another type of cell having more specialized functions. In body, stem cells can differentiate into other kind of body cells by having the following capabilities;
1) Proliferation; The stem cells are capable to renew even after long periods of inactivity and capable of self-renewal during cell division.
2) Unspecialized; They are unspecialized which later give arise to specialized cells.
3) Differentiation; They are able to differentiate them under special conditions and functions.
There are two kinds of stem cell:
1) Embryonic stem cells. Those stem cells are derived from developing embryo. These cells are mostly use for in-vitro fertilization.
2) Somatic stem cells. Commonly known as ‘adult stem cell’. They are defined according to their location within the body.
Difference between embryonic and somatic stem cells
Embryonic stem cells Somatic
Pluripotent. Non pluripotent.
Can easily grow in culture Not that easy. A large number of cells are required for stem cell replacement therapies.
Types of Somatic stem cells
The somatic stem cells can be further classified into mesenchymal stem cells and hematopoietic stem cells. The somatic stem cells are found in specific region of organ known as stem cell niche. The organs from where stem cell niche are found are in brain, skeletal muscle, gut, liver, pancreas, bone marrow, ovarian epithelium teeth, and testis.
The Somatic stem cells have been demonstrated as;
Hematopoietic stem cells; Give rise to all kinds of blood cells.
Mesenchymal stem cells; Give rise to all kinds of bone cells.
Neural stem cells; Give rise to all kinds of neuronal and non neuronal cells in brain.
Epithelial stem cells; Give rise to different kinds of cells of digestive tract.
Skin stem cells; give rise to all the epidermis and ketatinocytes of skin.