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Definition
| difference in electrical charge btwn inside and outside of a cell |
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Definition
neuron's steady membrane potential of about -70mV
Neuron is polarized |
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| Ions cause resting potential? |
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Definition
| Ration of negative to positive charges is greater inside neuron than outside |
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Definition
| more likely to move from areas of high concentration to low... get less crowded! |
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Term
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Definition
-Accumulation of charges
-repulsion of like charges in vicinity
-attraction of opposite charges elsewhere |
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| 4 kinds of ions that contribute to resting potential |
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Definition
- Na+ Sodium
- K+ potassium
- Cl- chloride
- various proteins-
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Term
| Cell membrane allows ions through, how? |
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Definition
| Cell membrane has PROTEIN CHANNELS that are very selective to allow passage of ions |
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Term
| Ions in Concentration Gradient |
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Definition
K+ OUT
A- OUT
Na+ IN
Cl- IN |
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Term
| Maintenance of Resting Potential |
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Definition
Sodium Potassium Pump
Cl- concentration gradient outside--> in
electrostatic pressure inside --> out
K+ concentration gradient inside--> out
electrostatic pressure outside--> in
Na+ concentration gradient outside--> in
electrostatic pressure outside--> in |
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Term
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Definition
chemicals that neurons release when they fire
diffuse across synaptic clefts
interact w/ specialized receptor molecules |
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Definition
| Neurotransmitters decrease resting membrane potential |
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Definition
| Neurotransmitters increase resting membrane potential |
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Term
| Excitatory Postsynaptic Potentials (EPSPs) |
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Definition
Postsynaptic depolarizations
increase likelihood neuron will fire |
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Term
| Inhibitory Postsynaptic Potentials (IPSPs) |
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Definition
Postsynaptic hyperpolerizations
decrease likelihood neuron will fire |
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Definition
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Definition
at threshold, sodium channels open btwn -65 and 50mV
at 50mV, sodium channels close
refractory period, then resting potential again |
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Definition
EPSPs and IPSPs can summate
Spacial: simultaneous on diff parts of receptive membrane sum to form greater
Temporal: rapid succession at same synapse sum to gorm greater signal |
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Term
At resting potential, more Na+/K+/Cl-
inside or outside neuron? |
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Definition
Na+/Cl- greater outside
K+ greater inside |
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Term
| Action Potentials originate...? |
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Definition
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Term
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Definition
| When the degree of depolarization of axon hillock exceeds the threshold of excitation |
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| Neurotransmitter release is caused by..? |
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Definition
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| Release of neurotransmitter molecules is often triggered by...? |
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