Stem Cells Explained | What are Stem Cells?

You might have heard about Stem Cells. Someone calls them the lifesaver, someone calls them lifemaker or sanjeevini booti संजीवनी बूटी |  Let us learn something more about them in this article.

What are Stem Cells?

Artistic picture of Stem Cell
Artistic picture of Stem Cell

Stem cells are a class of undifferentiated cells that are capable of giving rise to indefinitely more cells of the same type and are able to differentiate into specialized cell types. 

Generally, these cells come from two main sources:

  1. Embryos (during the blastocyst phase)
  2. Adult tissue

Adult Stem Cells

Adult or somatic stem cells exist throughout the body after embryonic development and are found inside of different types of tissue. These cells have been found in tissues such as bone marrow, blood, blood vessels, the brain, skeletal muscles, skin, and the liver.

They remain in a quiescent (non-dividing) state for years until activated by disease or tissue injury. They can divide indefinitely, enabling them to generate a range of cell types from the originating organ. 

Embryonic Stem Cells

Blastocyst showing Trophoblast & Embryoblast

Embryonic stem cells are derived from a 4-or 5-day old human embryo that is in the blastocyst phase of development. The blastocyst consists of an inner cell mass (embryoblast) and an outer cell mass (trophoblast). The inner cell mass is the source of embryonic stem cells that are totipotent cells i.e. cells with the total potential to develop into any cell in the body.

These stem cells are extracted by placing the “inner cell mass” of the blastocyst into a culture dish containing a nutrient-rich medium. Medium lacks the necessary stimulant so they do not differentiate. They begin to divide and replicate while maintaining their ability to become any cell type in the human body. Eventually, these undifferentiated cells can be stimulated to create specialized cells.

Stem Cell Cultures

Picture of Stem Cell
Picture of Stem Cell

Stem cells are either extracted from adult tissue or from a blastocyst in a culture dish. Once extracted, scientists place the cells in a controlled culture that prohibits them from further specializing or differentiating but usually allows them to divide and replicate. The process of growing large numbers of embryonic stem cells has been easier than growing large numbers of adult stem cells. But this progress is being made for both types of cells.

Stem Cell lines

Once stem cells have been allowed to divide and propagate in a controlled culture, the collection of healthy, dividing and undifferentiated cells is called a stem cell line. Once under control, these cells can be stimulated to specialize as directed by a researcher. This process is known as directed differentiation. Embryonic stem cells are able to differentiate into more cell types than adult stem cells.

Stem cells extracted from embryos can be induced to become any desired cell type. This property makes them powerful enough to regenerate damaged tissue under the right conditions.


These cells have unlimited potential in the field of medical science. Stem cells can be used in the treatment of Cardiovascular diseases, diabetes, neurodegenerative disorders and many more. These can help in bone regeneration and wound healing.

Scientist preserving Stem Cells in liquid nitrogen.
Scientist preserving Stem Cells in liquid nitrogen.

These have immense potential for treating a number of human diseases. Utilization of these cells to generate tissues and organs grafts will hold the tremendous success rate. This will decrease the chance of graft/ transplant rejection by the patient’s immune system.

If you liked this post, you can check more awesome post like GMO, DNA & its packaging.

Rakesh Barwar
Rakesh Barwar
Founder and Editor-in-Chief of The Last DNA. My passion for technology and biotechnology give rise to this awesome site. I write articles that can be easily understood by a majority of people, therefore making biotech simple and interesting!


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