Stem Cells: Characteristics and Importance. “Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth.”

NIH Stem Cell Information

What is a Stem Cell?

A stem cell, also known as a progenitor cell, is a type of cell capable of generating more specialized mature cells to form tissues and organs with specific functional characteristics. These stem cells give rise to all other cells, known as daughter cells, which are morphologically and functionally different from the stem cells.

A stem cell can produce a large number of specialized cells in both variety and number.

There are both embryonic and adult types. Embryonic stem cells are found only in human embryos aged six to eight days and can construct an entire organism, whereas adult stem cells assist only in cases of tissue or organ damage. The image below shows an example of an embryonic stem cell.

Finally, to learn more about Stem Cells, read our article What Are Stem Cells?

Where are Stem Cells Found?

Adult stem cells come in various types, each located in different zones depending on the tissues they will form. For example, stem cells in the bone marrow generate blood cells.

They are also found in the liver, forming hepatocytes, in neuronal tissue forming neurons, and muscles, among others.

Embryonic stem cells are located within the inner cell mass of the embryonic blastocyst.

Characteristics of Stem Cells

Stem cells are unique due to two key characteristics:

Potentiality: Stem cells can generate mature cells of different origins, such as blood or muscle cells. Self-renewal: They can divide and proliferate indefinitely to produce other stem cells. Their telomeres are longer than those of already differentiated cells, an important feature in cell division since cellular aging is related to telomere shortening.

Additional characteristics include:

• Indifferentiation: They are not mature cells and remain undifferentiated.
• Low Immunogenicity: They do not trigger an immune response as if they were external agents.
• Types of Division: They exhibit both symmetric and asymmetric division. The symmetric division produces two stem cells from the division of an initial cell. Asymmetric division results in one differentiated cell and one stem cell.
• Protective Mechanisms: They have high protection against external agents and a detoxification system against toxic agents in the cell.

Functions of Stem Cells

Stem cells are essential for forming multicellular adults from an embryo, allowing the development of all cell types needed to form organs with specialized tissue functions.

Another critical function of stem cells is tissue repair in developed organisms.

Without stem cells, wounds would be lethal, and internal organ deterioration would be unavoidable. The image below illustrates a tissue regeneration process example.