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Definition
| the "upstream" neuron which is the source of the current |
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Definition
| the "downstream" neuron into which this current flows |
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Definition
| links the membranes of two communicating neurons; an intercellular specialization |
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Definition
| precisely aligned, paired channels found in gap junctions |
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Definition
| ion channel proteins that make up connexons |
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Definition
| the space between the pre- and postsynaptic neurons in chemical synapses |
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Definition
| small, membrane-bound organelles within the presynaptic terminal that are key to chemical synapses |
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Definition
| chemical signals secreted from the presynaptic neuron; fill the synaptic vesicles; act as messengers between the communicating neurons; give the chemical synapse its name |
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Definition
| a neurotransmitter that acts to control heart rate |
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Definition
| molecules (transmitters) of different types present within a nerve terminal |
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Definition
| the mechanism that transports the enzymes needed to synthesize transmitters after they are produces in the neuronal cell body; transports them to the nerve terminal cytoplasm at a rate of 0.5 - 5.0 mm per day |
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Term
| small clear-core vesicles |
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Definition
| vesicles which package small-molecule neurotransmitters; 40 - 60 nm in diameter; center is clear in electron micrographs |
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Definition
| the process by which peptide-filled vesicles are transported along an axon & down to the synaptic terminal after having been synthesized in the cell body of the neuron |
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| large dense-core vesicles |
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Definition
| vesicles which package neuropeptides; 90 - 250 nm in diameter; center appears electron-dense in electron micrographs |
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Definition
| saucer-like looking sites on the muscle fiber where the presynaptic axon elaborates its terminals; synapses between spinal motor neurons and skeletal muscle cells; large, simple, peripherally located; good for experimental analysis |
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Term
| 3 steps to identify the identity of a neurotransmitter at a synapse |
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Definition
1. neurotransmitter present in presynaptic terminal
2. neurotransmitter released via action potential
3. neurotransmitter receptors activated |
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Definition
| the retrieved vesicular membrane passes through a number of intracellular compartments & is eventually used to make new synaptic vesicles |
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| the precursors to synaptic vesicles originally are produced in the _____ and _____ in the neuronal cell body |
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Definition
| endoplasmic reticulum; Golgi apparatus |
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Term
| which ion is crucial for neurotransmitter secretion? |
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Definition
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Term
| ionotropic receptors/ligand-gated ion channels |
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Definition
| a family of receptor proteins that contain a membrane spanning domain that forms an ion channel & combines transmitter-binding and channel functions into a single molecular entity |
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Term
| metabotropic receptors/G-protein-coupled receptors |
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Definition
| a family of neurotransmitter receptors where the eventual movement of ions through a channel depends on intervening metabolic steps |
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Definition
| intermediate molecules that are activated by metabotropic receptors to affect ion channels |
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Definition
| the macroscopic current resulting from the summed opening of many ion channels |
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Definition
the potential where the EPC reverses
ex) 0mV in the case of the neuromuscular junction |
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Term
| equation for the value of EPC |
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Definition
EPC = gACh (Vm - Erev)
gACh: the ionic conductance activated by ACh
Vm = potential
Erev = reverse potential |
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Term
| does the action of a transmitter drive the postsynaptic membrane potential toward or away from Erev for the particular ion channels being activated? |
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Definition
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Definition
| the current generated by the conductance change that depends on whether the channels are opened or closed (conductance increases when channels are opened, decreases when channels are closed) |
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Term
| postsynaptic potential/PSP |
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Definition
| a change in the postsynaptic membrane potential due to a PSC |
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Definition
| a postsynaptic potential that increases the likelihood of a postsynaptic action potential occurring |
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Definition
| a postsynaptic potential that decreases the likelihood of a postsynaptic action potential occurring |
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Definition
| activation of multiple EPSPs/IPSPs at a time so that their effects "sum" together; allows subthreshold EPSPs to influence action potential production |
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