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43 Cards in this Set
- Front
- Back
Which Neurotransmitter is used at the neuromuscular junction?
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ACh
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ACh binds to what kind of receptors?
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Nicotinic Acetylcholine Receptors
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The depolarization of the post-synaptic cell (muscle) at the NMJ is called:
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End-Plate Potential
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ACh is broken down by what?
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Acetycholinesterase
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Small fluctuations in the resting potential of a post-synaptic cell
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Miniature End-Plate Potentials (MEPP)
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Under normal circumstances, and EPP is always ________.
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Supra-threshold and will produce a muscle AP.
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Aparalytic toxin that prevents Action Potentials:
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Curare
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An autoimmune diease affecting NMJs becuase circulating antibodies block ACh receptors on the post-synaptic surface.
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Myasthenia Gravis
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How is Myasthenia Gravis treated?
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With cholinesterase inhibitors or immunosuppressants
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Neuromuscular disorder causing progressive muscle weakness:
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Lambert-Eaton Syndrome
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Disease involving the destruction of presynaptic calcium channels:
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Lambert-Eaton Syndrome
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The amount of transmitter released at the presynaptic membrane depends directly on:
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The duration of the action potential (longer APs lead to a greater influx of Ca2+)
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Region of muscle membrane that holds the synapse:
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End plate
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The large end plate potentials are a direct result of what?
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Very high concentration of ACh receptors on the end-plate membrane
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Which disease is often linked with small cell lung cancer?
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Lambert-Eaton Syndrome
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_________ results in in prologation of conduction time in nerve conduction velocity tests.
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Demyelination
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___ ______ leads to loss of nerve or muscle potential amplitude in nerve conduction velocity tests.
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Axonal Loss
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Specialized junction between nerve cells that has little time delay and allows for bi-directional flow:`
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Gap (electrical) junctions
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___ ________ allow ions and wiater soluble molecules to pass from cell to cell.
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Gap Junctions (large enough for amino acids and sm. peptides)
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___ _______ are found in neurons in the brain:
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Gap Junctions (CN V, inf. olivary nucleus)
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Proteins that make up gap junctions:
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Connexins
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Hundreds of gap junctions assemble into a macromolecular complex called:
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a plaque
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How can you modulate an elecrical synapse?
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Can be found in open or closed states that can be regulated by something as simple as calcium levels and pH.
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____ _______ are much larger than most other channels and not specific to any ion species.
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Gap Junctions
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Which ion channels are usually selective for NA+>K+?
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Voltage gates channels
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Which channels treat Na+ = K+ > Ca2+ = Mg2+.
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Transmitter/Chemical Gated Channels
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The _______ _______ is the patch of membrane with the lowest threshold potential, because it has the highest conc. of voltage gated Na+ Channels.
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Trigger Zone
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ThBoth EPSPs and IPSs are _________ conducted from the synapse to the axon hillock.
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Passively (electronic propogation)
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Why is temporal summation effective?
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Because APs are much shorter in duration than EPSPs.
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Respiration and cycles of wakefullness and sleep may involve these types of circuits which are arranged in a circular fashion:
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Oscillating Circuits (act as a positive feedback system)
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Neuromuscular transmission is always ________ whereas neuron-neuron synapses may be what?
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Excitatory, but neuron-neuron may be excitatory or inhibitory.
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Almost all muscle fibers are innervated by what?
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A single motor neuron.
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Neurons generally receive input from what?
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Several pre-synaptic cells
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If the reversal potential for the EPSP is near 0mV what does this indicate?
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It indicates the involvement of a non-selective monovalent cation channel allowing both K+ and Na+ to flow.
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______ generally produce and increase in the permeability of the post-synaptic membrane to K+ and or Cl-
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IPSPs
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Dy definition, the reversal potential for IPSPs is ______ to the threshold potential.
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Negative
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In cells where Cl- is passively distributed, the opening of Cl- channels will do what?
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Hold the membrane potential negative to threshold and reduce the influence of EPSPs.
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GABA is what kind of neurotransmitter (EPSP or ISPSP)
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IPSP - it activates a receptor that directly activated a Cl- channel
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Name two inhibitoty neurotransmitters that utilize Cl- channels.
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GABA and Glycine
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_______ ________ occurs when simultaneously propogating PSPs from two or more inputs combine on the membrane.
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Spatial Summation
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_______ _______ occurs when a single input fires rapidly enough that a second EPSP occurs before the first is over.
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Temporal Summation
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When one source provides output to many targets.
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Synaptic Divergence
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When multiple sources arrive onto one neuron or class of neurons.
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Synaptic divergence.
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