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45 Cards in this Set
- Front
- Back
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Nerve |
neuron in the periphery |
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Soma |
cell body with the nucleus |
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Types of neurons |
unipolar pseudo-unipolar bipolar multipolar (spinal motor neuron, pyramidal cells, Perkinje cells) |
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Types of glial cells |
astrocytes oligodendrocytes microglia radial glia |
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Astrocytes |
personal trainer to the neuron; remove inert chemicals, provide energy to neurons, neurotransmitter synethesis
-pull nutrients out of the capillaries and into the neuron; take waste from neuron and put it back in the bloodstream |
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Oligodendrocytes |
myelinate neurons |
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Microglia |
closest thing to immune cells in the brain; privileged brain immune cells |
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Radial glia |
development; act as a highway that neurons can travel down to get where they need to be during development/growth |
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Sodium-potassium pump |
2 K in, 3 Na out -requires ATP -keeps neuron at resting potential |
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Determinants of ion movement across cell membrane |
electrostatic forces and diffusion potential |
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Gated ion channels |
require specific conditions for ions to be let in or out -activity from other neurons and intracellular voltage open and close gated channels |
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Excitatory Post-Synaptic Potential |
cells start to become depolarized (inside becomes increasingly positive) |
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Inhibitory Post-Synaptic Potential |
cells start to become hyperpolarized (inside becomes increasingly negative) |
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Threshold of excitation |
point at which enough EPSPs occur that the cell can generate an action potential |
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Voltage-gated ion channels |
sensitive to overall voltage of the neuron -open as the overall charge becomes increasingly positive -voltage-gated sodium and potassium channels open when neuron is sufficiently positive |
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Spatial summation |
EPSP inputs from several different points can excite cell enough for an action potential |
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Temporal summation |
several EPSP inputs from the same space in a short period of time can generate an action potential |
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Axon hillock |
site of lots of voltage-gated sodium channels that propagates down, then immediately close so that the AP can't flow back down the axon (local depolarization, then closing of channels) |
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Myelin |
fatty sheath that covers the axon and greatly speeds up propagation of action potentials (almost all reflexes are controlled by these) -Nodes of Ranvier let sodium in at the gaps in the myelin sheath to depolarize and make action faster |
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Ligand |
any molecule that bonds to another molecule |
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Receptor |
large protein that responds to ligand bonding |
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Neurotrasmission |
communication between neurons -involves release of endogenous ligands (neurotransmitters and neuromodulators) that bind to receptors to alter neuron function |
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Vesicles |
tiny spherical packets in presynaptic terminal that hold neurotransmitters for release |
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Exocytosis |
release of neurotransmitter from presynaptic terminal into the synaptic cleft -dependent on Ca+ influx into the presynaptic terminal (caused by AP propagation) |
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Neurotransmitter (defining features) |
-present within presynaptic neuron -released in response to depolarization -receptors specific to neurotransmitter on post-synaptic terminal -neurotransmitter terminated or removed from synapse |
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Neuromodulator |
slower-acting than neurotransmitters -haven't been found to fit all criteria for neurotransmitter |
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Receptor activation |
alters influx of ions into neurons (lead to EPSP or IPSP) |
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Ionotrophic receptors |
receptors, when activated by attachment of a neurotransmitter, let in only specific ions |
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G-protein coupled receptors |
activate second-messenger systems -like a relay race, allows an amplified signal or cascade effect) -can trigger many different occurrences in a way that other receptors can't due to the use of alpha, beta, and gamma unit activation -alter membrane potential and gene activity |
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Common second messengers |
Calcium Cyclic AMP Cyclic GMP IP3 and DAG |
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Glutamate |
-ubiquitous neurotransmitter -excitatory -receptors: AMPA, NMDA, kainate, metabotropic |
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GABA |
-ubiquitous inhibitory neurotransmitter -GABAa: ionotropic brake -GABAb: metabotropic -acts as a brake in the CNS -promotion of GABA has been used to help sleep and anxiety disorders |
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Serotonin (5-HT) |
-roles in sleep, arousal, aggression, and mood -acts on metabotropic receptors -cell bodies in the Raphe Nucleus (only a few hundred serotonin projections in the brain) -drugs that promote serotonin are used as anti-depressants |
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Dopamine |
-metabotropic receptors -localized in Ventral Tegmental Area, Substantia Nigra, and arcuate nucleus of hypothalamus |
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Mesolimbic pathway |
originates in VTA and projects to limbic system -involved in motivation behaviors, arousal, reinforcement, and reward **significant role in addiction** |
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Mesocortical pathway |
originates in VTA and projects to frontal cortex -significant role in schizophrenia |
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Nigrostriatal pathway |
originates in substantia nigra and projects to dorsal striatum (of basal ganglia) -significant role in Parkinsons |
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Arcuate nucleus |
tuberoinfundibular pathway -dopamine release from this pathway inhibits lactation |
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Norepinephrine |
-involved in stress and arousal -contributes to anxiety disorders and PTSD |
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Acetylcholine |
-role in learning & memory, cognition, and arousal -localized in brainstem -neurons degenerate in Alzheimer's -two receptor types: muscarinic and nicotinergic |
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Neurotransmitter synthesis |
assembled from smaller molecules (dietary source) -assembled at axon terminal |
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Neuropeptides |
more discrete in localization and function than neurotransmitters -almost exclusively act through g-protein coupled receptors -spread more around the brain, don't send distant projections |
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Synaptic vs. volume transmission |
Synaptic: discrete, localized to the synapse Volume: released from varicosities, involved in neuropeptide release, allows neuropeptide to interact with many post-synaptic neurons |
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Neuropeptide synthesis |
cleaved from larger precursor molecules in the golgi apparatus |
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Ways neurotransmitters are removed from the synapse |
Transporters: suck up NT from synapse Enzymes: metabolize NT |
