Lecture 24 Stem Cells and Cell Differentiation

Lecture 24 Stem Cells and Cell Differentiation - IPHY 3060...

Info iconThis preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
IPHY 3060 Lecture 26: Stem Cells and Cell Differentiation
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Cell Birth and Development During human development, a single unspecialized cell must give birth to roughly 100 trillion cells In addition, these cells must become specialized for their particular function
Background image of page 2
Stem Cell: Unspecialized cell that can divide to produce another stem cell and a more specialized cell
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Cell Potential or Potency Fertilized egg or zygote —totipotent —can give rise to all cell types Embryonic stem cells pluripotent—can give rise to some but not all cell types Adult stem cells— unipotent--can only give rise to one cell type un un
Background image of page 4
Stem Cell Key Point #1: In general, cell potential/potency becomes restricted during development
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Stem Cell Key Point #2: A stem cell is self-replicating, i.e., it must give rise to another stem cell, otherwise the stem cell population will die out
Background image of page 6
Stem Cells during Development: Embryonic Stem Cells
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What are Embryonic Stem Cells? Embryonic stem cells are cells isolated from the inner cell mass of a blastocyst , which are pluripotent and can form nearly all of the 200 or so adult cell types if properly treated
Background image of page 8
Embryonic Stem Cells, the Blastocyst, and the Inner Cell Mass First 3 divisions—all cells still totipotent After ~6 divisions (4-5 days), cell mass is a blastocyst, which contains two pluripotent cell types: 1) trophoectoderm forms placenta 2) Inner cell mass —forms embryo
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Early Embryonic Specification-- Gastrulation Gastrulation —inner cell mass/embryo eventually forms a ball of cells which folds in on itself to form a 3 layered structure called the gastrula
Background image of page 10
3 Layers of the gastrula will eventually form different tissues 1) Ectoderm —skin, nerves, etc. 2) Mesoderm muscle, blood and bone 3) Endoderm internal organs— lungs, liver, intestines, etc.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
How do cells in the different layers know they are supposed to form these tissues? Because they receive novel signals from surrounding cells and matrix
Background image of page 12
Restriction of cell fate—at some point the cells in the developing embryo stop receiving the same signals Cell-cell interactions Distance from morphogens Ectoderm Mesoderm Endoderm Different cell-cell and Cell-matrix interactions
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Cell-cell signaling: Notch and Delta Notch on one cell binds to delta receptor on adjacent cell and initiates intracellular signals Helps establish dorsal-ventral patterning
Background image of page 14
Morphogens—secreted factors that form gradients and help specify geography or location Fibroblast growth factors 4 and 8 - proximal-distal patterning Wnt7a —dorsal- ventral patterning Sonic hedgehog posterior-anterior patterning Retinoic acid anterior-posterior patterning
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Key Point: Cell-cell interactions and morphogen signals activate expression of master transcription factors which in turn activate groups of genes which further restrict cell fate by defining the location and identity of cells that express them
Background image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/11/2010 for the course IPHY 3060 taught by Professor Allen,davi during the Fall '09 term at Colorado.

Page1 / 68

Lecture 24 Stem Cells and Cell Differentiation - IPHY 3060...

This preview shows document pages 1 - 17. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online