stem cells
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Cell Differentiation and Stem Cells
Major Topics for Discussion:1) What are Stem Cells?2) What are the major types of Stem
Cells and where are they found?3) Advantages & Disadvantages to
ESCs and ASCs4) Why are Stem Cells so very
important? 5) The Controversy over Stem Cells? 6) What are the new advances in
stem cell research?
What is cell differentiation?
• When unspecialized cells develop into specialized cells
• All cells have the same DNA but different genes are turned on in different cells.
• Also a cell’s location determine what it will become
Plants vs animals
• Animal cells can migrate to different areas but plants cannot.
• Outer layer becomes skin and nervous system.
Middle layer becomes bones and muscles.
Inner layer forms internal organs.
What are Stem Cells?Stem Cells are extraordinary because:• They can divide and make identical copies of themselves over and over again, self- renewal
• Remain Unspecialized with no ‘specific’ function or become . . . .
• Specialized (Differentiated) w/ the potential to produce over 200 different types of cells in the body.
Embryonic Stem Cells - come from cells of the blastocyst
(5-day old embryo) from IVF (In Vitro Fertilization) procedures
http://www.hhmi.org/biointeractive/media/human_emb_dev-lg.mov
Adult stem cells have been found in many organs and tissues, including brain, bone marrow, blood
vessels, skeletal muscle, skin, teeth, heart, corneas, liver, ovaries, and testis.
Go GGo Go Stem Cells!to see how adult stem cells work
http://learn.genetics.utah.edu/content/tech/stemcells/sctypes/
Stem cells are classified
• According to their potential to develop into other types of cells.
• Embryonic stem cells can develop into almost any type of cells but adult stem cells only give rise to closely related cells.
Stem Cell Classification:
• Totipotent stem cell – can grow into any type of cell…only in fertilized egg or very early embryos (5- days)
• Pluripotent stem cell – can give rise to almost any cell…in early embryonic cells
• Multipotent stem cell – adult stem cell, only gives rise to closely related cells
Advantages and Disadvantages to Embryonic and Adult Stem Cells.
Embryonic S.C. Adult S.C.“Pluripotent”
(can become almost any cell)
“Multipotent”“(can become many
but not all)
Stable. Can undergo many cell divisions.
Less Stable. Capacity for self-renewal is limited.
Embryo is destroyed. Difficult to isolate in adult tissue but not a moral issue
1) Transfer nucleus from a mature cell into a donor egg whose nucleus has been removed.2) Stem cells isolated from blastocyst tobe induced to formneeded tissues
Why is Stem Cell Research So Important to All of Us?
Stem cells can replace diseased or damaged cells
Stem cells allow us to study development and genetics
Stem cells can be used to test different substances (drugs and chemicals)
Stem Cell Therapy has the Potential to:
• Regenerate tissues/organs
• Cure diseases like diabetes, multiple sclerosis, etc.
What Human Diseases are Currently Being Treated with Stem Cells?
• Cancer• Auto-immune diseases• Cardiovascular• Ocular (cornea)• Neural diseases• Wounds/injuries• Anemias and blood diseases
Technical Challenges
• Source - Cell lines may have mutations.
• Delivery to target areas
• Prevention of rejection
• Suppressing tumors
Why the Controversy Over Stem cells?• Embryonic Stem cells are derived from extra
blastocysts that would otherwise be discarded following IVF.
• Extracting stem cells destroys the developing blastocyst (embryo).
-Questions for Consideration-Is an embryo a person?Is it morally acceptable to use embryos for
research?When do we become “human beings?”
Teachers' Domain: Stem Cells: Seeds of Hope?
Current research
• New Research points to a new direction in Stem Cell Research
Teachers' Domain: Stem Cells Breakthrough
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