L312/Spring 2007Lecture 24Drummond April 17

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L312/Spring 2007 Lecture 24 Drummond April 17
For today Finish Chapter 21 Stem cells and
cell differentiation Third exam Thursday,
April 19th Review sessions
Today/tomorrow? Old Focus on connections
between cells (mostly epithelial layers
(tissue)) tight junctions claudins and
occludins adherens junctions actin bundles
connected by cadherins desmosomes intermediate
filaments (keratins) con. by cadherins hemides
mosomes keratins connected to integrins con. to
basal lamina gap junctions connexins span
four membranes to form pore Formation of
tubules constriction of actin rings in
individual cells connected by adherens
junctions in a layer of tissues New How
tissues are maintained and replaced? where do
new cells (and many cancers) come from? what
maintains cells in a differentiated state in a
tissue? what are stem cells, and why are they
important? what kinds of cell types are likely
to initiate tumorigenesis?
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How are epithelial cells interconnected?
Focus on the key proteins and structures That
allow contact and communication
3
How can tubes be generated during development?
Folding a two- Dimensional Surface here
4
Tissues need not be comprised of identical
cells (note specialized cells for absorption and
secretion!)
5
Stepping back cells in the context of structure
Goblet and absorptive cells
How are such highly organized tissue structures
generated? What happens when a cell dies?
6
What cell-cell events support tissue formation
and why?
(Epigenetic)
Which events prohibit proliferation?
7
Think of tissues in terms of multiple cell types
(and contributions)
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Where do new tissue cells come from?
How does this compare with bacterial cells? Why
does this hold promise for disease treatment?
9
Tissue renewal in the gut--where are new cells
born
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Where are new cells born II--skin cells
How does this arrangement help protect
individuals from skin cancers?
11
Cell types circulating in the blood
What determines the surface structure?
(what kind of microscope image is this?)
12
What is the origin of the different blood cell
types?
What do these cell types do? How can so many cell
types be generated?
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How is differentiation controlled?
What are the therapeutic implications for stem
cells?
What classes of TM receptors (usually) transduce
slower, longer-term effects (respond to GFs and
hormones)
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Creating embryos from adult (differentiated)
genomes
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Todays discussion topic why and how do cells
evade home tissue?