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36 Cards in this Set
- Front
- Back
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What neuron type is found in the cerebellum?
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Purkinje Cells
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Describe the shape and structure of dendrites.
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Dendrites: tapered (get thinner), branch at ACUTE angles; integrate signal
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How does dendrite length affect signal transduction?
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The longer the dendrite, the greater the signal decrements
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In terms of signal propagation, how is plasticity achieved?
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Signals can propagate backwards (from soma to dendrite)
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How is the cerebral cortex 'laminated'?
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It has 6 layers
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Structures Nissl can stain?
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stains somas of neurons/glial cells (proteins)
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Structure Golgi can stain?
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Entire neuron
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Size of a dendritic spine?
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About 1 micron
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Mechanism of Tay-Sachs
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Accumulation of membrane in dendrites, can't conduct information, results in MR, Death (enlarged dendritic processes; aka MEGANEURITES)
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What effect would lack of nutrition during development have on dendrites?
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Growth restriction; dendrites won't receive information because can't reach!
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What effect does estradiol have on dendrites? What else could cause this?
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Irregular spines (loss of spines, more spread out along dendrites)
Also caused by other hormones, aging, MR, FRAGILE X |
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Describe the shape and structure of axons.
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NOT tapered, branch at right angles, no spines
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Give an example of a neuron that has a large diameter and is myelinated.
Give an example of a neuron that has a smaller diameter. How do they differ? |
Large diameter and myelin = Fast conducting, ex: PROPRIOCEPTORS
Small diameter = Slow conducting; carry slow (burning) pain, temperature |
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List two ways that Schwann Cells differ from Oligodendrocytes.
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Oligos are in CNS; one oligo can form many layers of myelin
Schwann Cells are in PNS; one Schwann cell per layer of myelin |
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Where is the highest concentration of sodium-channels found on a neurons? Why is this important?
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Found on axon hillock; when depolarized fires an IMPULSE which is propagated UNDECREMENTED
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How does action potential propagation differ among myelinated and unmyelinated axons?
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Myelinated: Saltatory; fast (AP propagates across Nodes of Ranvier); Faster
Unmyelinated: depol occurs locally, creeps down membrane, doesn't 'jump'; Slower |
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List two ways that C-fibers differ from A-delta fibers
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A-delta: FAST pain fibers; medium thickness
C-fibers: SLOW pain fibers; thin axons (dull, aching pain) |
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What is the mechanism of onset of Guillain-Barre Syndrome?
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AKA Acute Inflammatory Demyelinating Neuropathy
Due to demyelination in PERIPHERAL axons |
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What is the mechanism of onset of Multiple Sclerosis?
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Demyelinatin in CNS
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What is the effect of cross-talk in demyelinated axons?
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Message leaks out and is no longer localized
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Fast acting excitatory NT
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Glutamate
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Fast acting inhibitory NT
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GABA
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Modulatory NTs
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DA
ACh NE Serotonin |
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Briefly describe the electrochemical events of a GABA-a-like synapse.
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IPSP!
Ca2+ in PreSyn GABA fuse, release, bind Cl- enters PostSyn (HYPERPOL) |
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Define receptor divergence.
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A single NT can activate multiple receptors (have multiple effects)
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Describe the three classes of GABA receptors.
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GABA a: Cl- channels (ligand)
GABA b: K+, Ca2+ (G-prot) GABA c: Cl- (ligand gated) |
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Effect of glycine?
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Inhibitory; Cl- (ligand)
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What can the modulatory sites of GABA a receptors bind? Effect of their binding?
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EtOH
Benzodiazepines Barbiturates Neurosteroids Result in greater sedative (Depressive) effect; Potentiate GABA |
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Field Potential VS Action Potential
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Field Potential: Electrical events in dendrites (Slow); reflect INPUT
AP's: axons, spikes (Fast); reflect OUTPUT |
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How do excited EEG waves differ from relaxed waves? How would these waves look in seizures?
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Excited waves are less synchronous (much smaller spikes)
Relaxed waves are more synchronous (bigger spikes) Waves would go from asynchronous to VERY synchronous |
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What is the major form of coding in the brain?
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Spikes (outgoing message); frequency of firing is a possible code
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Approximately how big is a soma?
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~30 microns
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