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18 Cards in this Set
- Front
- Back
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How are dendrites (input, integrate signals) different from axons in shape and "direction"
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dendrites: taper, branch at acute angles
axons: don't taper, branch at right angles |
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As EPSPs propagate down a dendrite how does the strength change?
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decreases
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Do dendrites have any retrograde information flow? (back towards synapse)
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Yes.
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Where does "higher brain function" occur?
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cerebral cortex
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How many "layers" are there in the cerebral cortex? can dendrites span more than one?
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6
yes. |
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In a nissl stain, what stains?
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soma (cell body) only
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what are the principle neurons in the cerebral cortex?
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pyramidal cells
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What are spines? where are they found?
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small "bumps" on dendrites; important for receiving synapses, maintenance and keep separate from adjacent synapses
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How big are spines?
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~1 micron
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in what disease would you see lipid accumulation in axons of cortical pyramidal cells?
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Tay Sachs (membranous cytoplasmic build up; seizures, mental retardation)
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what effect would chronic placental insufficiency have on neurons?
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growth restriction; smaller dendrites = missed information
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what factors affect spine shape, number, and biochemistry?
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genetics, environment, age
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What do corticospinal axons travel through? corticocortical going from L to R hemisphere?
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internal capsule
corpus callosum |
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What types of cell make myelin in the CNS? PNS?
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Oligodendrocytes (CNS; one can myelinate several axons)
Schwann cells (PNS; one can only myelinate one axon) |
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What characteristic of the initial axon segment plays role in AP conduction?
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very high concentration of Sodium channels (highest at this point on axons, others at Nodes of Ranvier)
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In a depol, what is the ion flow?
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Na+ in, K+ out
(in myelinated axons, AP propagation called "saltatory conduction") |
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What disease is associated with de-myelination in the PNS? CNS?
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PNS: Guillain-Barre syndrome (lose communication, paralyzing)
CNS: multiple sclerosis |
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Does de-myelination kills the axon itself? How does is cause harm?
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No.
-slows conduction -then block conduction - cause axon-to-axon crosstalk |
