Human embryonic development



Human embryonic development

determination Vs differentiation

stem cells precursor cells specialized cells

cell division cell movement cell adhesion changes

inner cell mass (ICM)

produce all tissues

gastrulation

three germ layers

most cells’ fate restricted (types of cells they can produce)

endoderm => pancreatic bud => only pancreas cells

Creating Embryonic Stem Cell Lines

early human embryos blastocyst

Remove inner cell mass (ICM)

Culture grow in lab indefinitely

Various growth factors => differentiate into variety of specialized cells

beating heart cells

Somatic cell nuclear transfer (SCNT) a cloning technique

Remove nucleus from healthy egg => egg now a host for nucleus transplanted from another cell (skin cell)

microscope & small glass pipettes to handle egg cells & to remove & transfer cell nuclei

resulting embryo can generate embryonic stem cells

therapeutic cloning ESC = genetic match to nucleus donor

reproductive cloning implant into surrogate mother => cloned individual (Dolly)

Stem Cell Capabilities

Still largely potential

Potential demonstrated by regeneration in other organisms

regenerative capabilities of the planarian

Urodele limb regeneration

Amputate

Stump cells dedifferentiate=> mass of stemlike cells

produce all the specialized tissues of the limb (muscle, nerves, blood vessels)

zebrafish heart

similar to human heart

unlike human heart, fish heart closes wounds rapidly & regenerates to nearly full function.

Fibroblast growth factor (FGF) important in regeneration

Stem Cells: Animations and Video Clips

Human Development and Stem Cells

Mapping Cell Fates

Creating Embryonic Stem Cell Lines

Cultured Human Embryonic Stem Cells

Somatic Cell Nuclear Transfer Video

Somatic Cell Nuclear Transfer Animation

Planarian Regeneration and Stem Cells

Newt Limb Regeneration

Zebrafish Heart Regeneration

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