Flashcards in Cellular Neuroanatomy (1) Deck (65)
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2 principal cell types in nervous system
Neurons and glia
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Structural and functional unit of the NS
Neuron
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3 functions of glia
1. Physical support ( protection)
2. Electrical insulation
3. Metabolic exchange b/n vascular system and NS
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Function of neuronal cell body. Other name?
Produces proteins and provides metabolic function. Also called soma
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Which neuronal structures receive input from other neurons.
Dendrites
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What kind of inputs are are preferentially on to dendrites and dendritic spines?
Excitatory synaptic inputs
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What three functions do dendritic spines serve as the anatomical substrate for?
1. Synaptic transmission
2. Synaptic plasticity
3. Memory storage
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How many axons does each neuron have? Function?
One and ONLY ONE axon. Axons conduct electrical output from one neuron to another.
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How many dendritic spines may be on a dendrite?
Hundreds to thousands. Remember they are the small membranous protrusions from the dendrites themselves, sort of like microvilli.
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Soma of neurons is esp. rich in what organelle?
Rough ER
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What are Nissl bodies?
Basophilic masses consisting primarily of rough ER and ribosomes. Function is protein synthesis.
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Positive Nissl stain indicates what 2 neuronal structures.
1. Cell bodies
2. Proximal dendrites
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Where is Nissl substance not found in neurons?
In the axon, beginning at the axonal hillock
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Gray matter is _________ tissue and consists primarily of what two neuronal structures?
Unmyelinated; consists of Somas and Dendrites
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White matter is ______ tissue; what neuronal structure does it primarily consist of?
Myelinated; consists of myelinated Axons
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What organelles are present in the axonal hillock.
None!
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What is the axonal initial segment?
Portion of axon from axonal hillock to beginning of myelination
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Pseudounipolar neurons are typically found where?
In the PNS, as part of sensory neurons. Ex. - sensory neurons with cell bodies in the dorsal root ganglia
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Where are multipolar neurons typically found
In the CNS. Ex. - pyramidal cells of cortical regions, Purkinje fibers of the cerebellum, or motoneurons
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Local circuit interneurons, such as those in the retina are usually what type of neuron?
Bipolar
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What type of cells integrate information and send long axons to other brain areas? Other two names for these?
Principal cells; also called projection neurons or Golgi type I cells
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What is unique about interneurons? What other two names are they known as?
They do not send their axons out of the local brain area. Also called Local Circuit neurons or Golgi Type II cells (either no axon or short, local axon)
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What are the two types of synaptic transmission?
Electrical and chemical
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What structures are needed for electrical synapses to function?
Gap junctions
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Most excitatory synapses in the brain are located on what structures?
Dendritic spines
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What are the 4 types of synapse types?
1. Axosomatic
2. Axodendritic
3. Axoaxonic
4. Dendrodendritic
The neuromuscular junction is also one; axospinous is a subtype of axodendritic
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What is unique about chemical synapses in vertebrates compared to electrical synapses?
Chemical synapses transmit information unidirectionally
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What is the presynaptic bouton or axonal varicosity?
Portion at end of axon where synaptic vesicles containing NT reside
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What are two examples of excitatory NTs?
Acetylcholine and glutamate
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