What Are Stem Cells?

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Living things are composed of different types of cells.

In humans, the structure of the body includes tissues and organs. Each of these organs has specialized cells from which they are made. These cells are considered the building blocks of life.

For example, your skin is made up of skin cells, your heart is composed of heart cells, and so on. These cells focus solely on their primary functions. However, there can be situations where one of them enters a state of emergency and needs repair.

• Who do cells call on when they need help?
• How do they do it?

What Are Stem Cells?

Stem cells do not belong to any specialized group of cells, like the heart cells. Instead, they have the unique ability to develop into many different forms.

Because stem cells are not classified as a particular type of cell, they are usually called neutral or foundational cells.

For example, stem cells are found within bone marrow in adults. If these stem cells come in contact with damaged liver tissue, they will convert themselves into healthy liver cells and repair the organ.

This ability to differentiate is not the only difference between stem and other cell types.

Unlike muscle cells, blood cells or nerve cells that do not normally make copies of themselves, stem cells are able to self-renew or make copies of themselves. In fact, stem cells are able to replicate millions of times.

• Are all stem cells the same?

Let's find out!

Types of Stem Cells

All humans start as embryos. During development, stem cells generate all the tissues and organs needed to create a baby.

Some of these stem cells remain in specialized areas of the adult body -- such as bone marrow -- as tissue-specific stem cells.

Embryonic Stem Cells

The stem cells found within a human embryo, and later a fetus, replicate into all the specialized cells that build and maintain the human body.

Embryonic stem cells are pluripotent, which means they can become any other cell. This makes them extremely unique and valuable.

Scientists are able to collect embryonic stem cells from embryos that are created in laboratories via in vitro fertilization (IVF).

Tissue-specific Stem Cells

Also known as somatic or adult stem cells, these are much more specialized than embryonic stem cells. They are only able to differentiate into the cell types found within the tissue or organ where they are found.

Adult stem cells also do not replicate as quickly or extensively as embryonic stem cells.

Induced Pluripotent Stem Cells

Induced pluripotent stem cells (iPS) are the result of recent breakthroughs in stem cell research. Scientists discovered a way to convert adult stem cells into ones that act like embryonic cells.

While iPS cells share many characteristics of embryonic stem cells, they are not exactly the same. Their differences are currently subject to further research.

The Future of Stem Cell Research

The ultimate goal of stem cell research is to find a reliable way to direct the differentiation of stem cells in order to treat damage and disease within the human body.

Stem cells are invaluable because they can be used to create brand new tissues and organs in laboratories and within the body. For example, a new heart could be generated in a laboratory with stem cells and then transplanted into a patient with a damaged heart.

Research on stem cells could help scientists understand why genetic defaults occur in cells and how diseases develop. New drugs can also be tested on stem cells.

Some medical conditions that could potentially be treated with stem cells include:

• traumatic spinal cord injury
• stroke
• severe burns
• rheumatoid arthritis
• heart disease
• hearing loss
• retinal disease
• Huntington’s disease
• Parkinson’s disease

Battling the Controversy

One of the biggest challenges of embryonic stem cell research is the question of ethics and morality.

Remember, harvesting the embryonic stem cells from an embryo prevents it from developing into a fetus and later a baby. This raises a lot of potentially difficult questions.

• When does life begin?
• If the research could save hundreds of lives, does that justify preventing an embryo from surviving?
• Is research a better fate for in vitro fertilized embryos that will never be allowed to develop into fetuses?

These are not questions that can be answered here or by anyone other than yourself based on your values and beliefs.

Fortunately, the continued breakthroughs in iPS cells may negate the need to use human embryos in stem cell research.

Delve a bit deeper into what you've learned about stem cells as you watch What Are Stem Cells | Genetics | Biology | Fuse School from FuseSchool - Global Education:

When you are ready, head over to the Got It? section to review some of the most important stem cell concepts!