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Stem Cells

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Stem Cells * * * * What is a Stem Cell? General Specific Unspecialized cells Give rise to more than 250 specialized cells in the body Serve as the body s repair ... – PowerPoint PPT presentation

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Title: Stem Cells


1
Stem Cells
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(No Transcript)
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What is a Stem Cell?
  • General
  • Specific
  • Unspecialized cells
  • Give rise to more than 250 specialized cells in
    the body
  • Serve as the bodys repair system
  • Self-Renewal
  • Differentiation (specialization)

4
http//www.nih.gov/news/stemcell/figure5.jpg
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Two types of stem cells
  • Embryonic (ES)
  • Adult (non-embryonic) (AS)

6
Stem Cells differ by
  • Origin
  • Embryonic
  • Adult
  • Different potentials
  • Totipotent
  • Pluripotent
  • Multipotent

Origin determines potential
7
Potentials
Totipotent - having unlimited capability.
Totipotent cells have the capacity to specialize
into extraembryonic membranes and all cells of
the embryo. Pluripotent -capable of giving rise
to most tissues of an organism. Multipotent
-capable of giving rise to many tissues of an
organism.
8
Definitions
  • Stem cells undifferentiated cells that have the
    ability to
  • divide for indefinite periods in culture
  • to become specialized cells
  • Differentiation
  • the process whereby cells become specialized
  • Produces stems cells with decreasing potential

9
Derivation
10
Embryonic Stem Cells (ESC)
  • Embryos are the result of In Vitro Fertilization
    (IVF)
  • Cells are taken from the Inner Cell Mass (ICM)
    of a blastocyst
  • ICM cells are nourished in a petri dish in an
    incubator
  • Cells are given different types of
    Factors/chemicals
  • These cells can give rise to most types of cells

11
In Vitro Fertilization (IVF)
  • Eggs are removed from ovary of female
  • Sperm is obtained from male
  • Egg and sperm are combined in test tubes/Petri
    dish
  • Fertilized eggs (zygotes) are allowed to divide
    for a few days.
  • Blastocysts are then transferred to uterus of
    woman
  • What happens to left over embryos?
  • Frozen until used again
  • Discarded

12
In Vitro Fertilization

Fertilization
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The zygote divides
Each cell is totipotent
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Blastocyst formation
The 1st sign of differentiation
Blastocyst
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Blastocyst
Gives rise to an embryo under proper conditions
These are now Pluripotent stem cells
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Embryonic Stem Cells
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Cell differentiation
Can divide
Can divide
Differentiation
Differentiation
Can divide
Differentiation
Differentiation
Pluripotent stem cell (Embryonic stem cell)
Multipotent stem cells (Adult stem cell)
Differentiated cells (muscle, nerve, skin,
fibroblast, etc)
18
Adult Stem Cells
  • Adult tissues reported to contain stem cells
    include brain, bone marrow, peripheral blood,
    blood vessels, skeletal muscle, skin and liver.
  • There are a very small number of stem cells in
    each tissue

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Why is research on embryonic stem cells important?
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Current Issues
  • Derivation
  • Induced-pluripotent stem cells
  • Ethics
  • Challenges
  • Controlling specialization
  • Donor acceptance

21
Importance of Stem Cells
  • Perhaps the most important potential application
    of human stem cells is the generation of cells
    and tissues that could be used for cell-based
    therapies.

http//stemcells.nih.gov/index.asp
22
Importance of Stem Cells
  • Today, donated organs and tissues are often used
    to replace ailing or destroyed tissue, but the
    need for transplantable tissues and organs far
    outweighs the available supply.

23
Importance of Stem Cells
  • Parkinsons Disease
  • Loss of dopaminergic producing nerve cell in
    substantia nigra
  • Severe motor disturbance
  • Fetal brain cells and iPS (reprogramming)
  • http//www.youtube.com/watch?v1yCgLythe00

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Importance of Stem Cells
  • Alzheimers Disease
  • Dementia
  • Death brain tissue, protein placques, hippocampus
  • http//www.youtube.com/watch?vzgvm_vvqq3Ifeature
    related
  • http//www.youtube.com/watch?vTZA3QFliteAfeature
    related

24
25
Importance of Stem Cells
http//www.youtube.com/watch?vvwCrxomPbtY
http//www.youtube.com/watch?vADchGO-0kGofeature
related
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