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12 Cards in this Set
- Front
- Back
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The initial outgrowth of the axon from cell body and its orientation appear to be genetically determined.
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True
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Where can you find a growth cone?
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At the tip of most growing neurites(axons and dendrites)
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What is a growth cone?
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A flattened region(lamellipodium) from which extend finger-like processes(filopodia) which are typically 5-30 um long and 0.1 um in diameter.
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What is the filopodia and leading edge of lamellipodia filled with?
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Fibrillar actin.
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The proximal region of the growth cone is packed with
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Cellular organelles.
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What can be deduced when growth cones are observed in vitro?
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Highly motile,dynamic structures constantly moving and exploring environment by extension and retraction of their leading edge and filopodia.
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What must be present for forward mvt to occur?
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Appropriate substratum onto which leading edge can attach and become stabilized.
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What happens to the actin monomers at the leading edge of growth cone?
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Polymerized,then swept rearward where they are depolymerized and then recycled to the leading edge where they are RE-polymerized.
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Continuous cycling of actin generates
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Caterpillar tread within interior of growth cone.
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Actin meshwork linked to cell surface receptors(integrins,NCAMS,cadherins)
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Bind to permissive susbtrate molecules(ECM molecules,laminin,fibronectin) so that meshwork remains in place.
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What does axonal pathfinding involve?
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Contact mediated and Diffusible
chemoattraction and chemorepulsion. |
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What are the molecular markers that integrin receptors on axons tips bind to?
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-ECM: laminin/fibronectin
-On neurons: N-CAM -On glia : G1-CAM |
