Term
Electrical Synapse
Chemical Synapse |
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Definition
Pass electrical signals directly from one neuron to another
Convert electrical signals into chemical signals
Chemical signals carried by neurocrines
Majority of synapses are chemical |
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Term
3 Primary Types of Neurocrines
Resting Membrane Potential in general neuron
What's inside/outside? Na/K pump? |
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Definition
Neurotransmitters
Neuromodulators
Neurohormones
-70mV
K inside and Na outside. Pump 2 K inside and 3 Na outside. - neg inside the cells and + outside. |
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Term
How is an Action Potential generated?
What is the Threshold number?
When do K channels trigger to open? |
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Definition
The resting potential must go from -70mV to -55mV, to do this Na channels open to allow to reach threshold, then K channels open to repolarize the cell to get to a resting potential. but overshoots because the K are slow to close. Then it gets back to the resting potential.
-55mV
30mV |
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Term
| Tetrodatoxin- Puffer fish |
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Definition
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Term
Neurotransmitters
Neuromodulators
Neurohormones |
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Definition
Diffuses across narrow synapse, has rapid effect removed from synapse quickly (Common: Acetylcholine, Norepinephrine, Dopamine, Nitrous oxide)
Released by neuron and remain in synapse
Diffuses into bloodstream, effect distant cells |
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Term
Synapse
Soma
Dendrtites
Axon
Axon Hillock
Axon Terminal |
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Definition
Site of communication between two neurons
Contains the nucleus and most organelles
Reception of incoming information
Transmits electrical signals called action potentials
Axon origin and where the AP is initiated
Releases NT |
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Term
Afferent
Efferent
Interneurons |
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Definition
From receptor to CNS
From CNS to effector
Stay within CNS |
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Term
Leak channels
Voltage-gated channels
Ligand-gated channels |
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Definition
Always open throughout neuron
Open or close in response to change in membrane potential
At end of axon, release neurotransmitters
Open or close in response to ligand binding
Open / close with neurotransmitter binding
Dendrites and cell body |
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Term
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Definition
Abnormal neuronal excitability
Random firing of populations of neural cells
Anticonvulsants can block Na+ channels, which would not allow Na to enter the cells to make the inside more positive to create an AP at -55mV. |
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Term
Activation gates
Inactivation gates |
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Definition
Voltage-dependent
Open with depolarization
Positive feedback
Voltage-dependent
Time-dependent
Open with depolarization
Close with repolarization
They “inactivate” the depolarization |
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Term
Refractory Period
Absolute refractory period
Relative refractory period |
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Definition
Period of decreased excitability following an action potential
Immediately follows action potential
No action potential possible
K+ channels open
Na+ channels closed
No AP possible!
Follows absolute refractory period
Action potential possible with stronger stimulusK+ channels open
Some Na+ channels reset
ready to open
AP possible only with very strong stimulus
Cell is hyperpolarized
Have to move from
>> -70mV to 30mV threshold |
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