Stem cells (SCs) have the potential to develop into many different types of cells in the body. They serve as a repair system for the body.
There are two main types of stem cells: embryonic SCs and adult SCs.
SCs differ from other cells in the body in three ways:
- They can divide and renew themselves over a long period of time.
- They are not specialized, so they cannot perform specific functions in the body.
- They have the potential to develop into specialized cells, such as muscle cells, blood cells, and brain cells
- Doctors and scientists are excited about SCs because they could help in many different areas of health and medical research.
Studying SCs may help explain how serious diseases such as cancer and birth defects occur. SCs could someday be used to create cells and tissues for the treatment of many diseases.
Examples include Parkinson’s disease, Alzheimer’s disease, spinal cord injury, heart disease, diabetes, and arthritis.
Stem cells have the capacity to divide asymmetrically giving rise to two daughter cells, one of which has the same properties as the original SCs and the other of which acquires the capacity to differentiate if the environmental conditions are suitable.
Most tissues of an adult organism have a resident population of adult SCs that allow their periodic renewal or regeneration when tissue damage occurs.
Throughout the life of the organism, populations of adult stem cells serve as an internal repair system that generates replacements for cells that are lost through normal wear and tear, injury, or disease. Adult stem cells have been identified in many organs and tissues and are generally associated with specific anatomical locations. These stem cells may remain quiescent (non-dividing) for long periods of time until they are activated by a normal need for more cells to maintain and repair tissues.NIH stem cell
Some adult stem cells are capable of differentiating into more than one cell type, such as mesenchymal SCs and hematopoietic SCs, while others are direct precursors of the cells of the tissue in which they are found, such as skin, muscle, intestinal, or gonadal SCs.
Embryonic stem cells are those that form part of the inner cell mass of a 4-5 day old embryo. They are pluripotent, which means that they can give rise to the three germ layers: ectoderm, mesoderm, and endoderm.
A fundamental characteristic of embryonic SCs is that they can be maintained indefinitely, forming a cell identical to themselves when dividing, and maintaining a stable population of stem cells.
There are experimental techniques where embryonic SCs can be obtained without destroying the embryo.
To learn more about stem cells, we invite you to see our article Stem Cells, what are they used for?