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23 Cards in this Set
- Front
- Back
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Glial Cells/Neuroglia |
Support and myelinate neurons. |
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Astrocytes |
Nourish neurons and form blood-brain barrier. |
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Ependymal Cells |
Line ventricles of brain and produce cerebrospinal fluid, physically supporting brain and absorbing shock. |
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Microglia |
Phagocytic cells that ingest and break down waste products and pathogens in CNS. |
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Oligodendrocytes/Schwann Cells |
Produce myelin around axons in CNS and PNS, respectively. |
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Depolarization |
Raising Vm from resting potential, making neuron more likely to fire an action potential. |
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Hyperpolarization |
Lowering Vm from resting potential, making neuron less likely to fire an action potential. |
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Threshold value |
When sufficiently depolarized to this point (around -55 mV to -40 mV), an action potential will be triggered. |
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Summation |
Additive effects of multiple signals. |
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Temporal Summation |
Multiple signals integrated during a short period of time. |
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Spatial Summation |
Additive effects are based on number and location of incoming signals. |
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Inactivated Sodium Channels |
When Vm approaches +35 mV, the sodium channels are inactivated. |
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Deinactivated Sodium Channels |
When inactivated sodium channels are brought back to their initial resting potential. |
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Repolarization |
Restoration of negative membrane potential as K+ ions are driven out of cell. |
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Absolute Refractory Periods |
No amount of stimulation can cause another action potential to occur. |
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Relative Refractory Period |
Requires a greater than normal stimulation to cause an action potential because membrane is starting from a potential more negative than its resting value. |
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Saltatory Conduction |
Signal hopping from node to node (Ranvier) due to stretches of myelin insulation. |
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Presynaptic Neuron |
Neuron preceding synaptic cleft. |
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Postsynaptic Neuron |
Neuron following synaptic cleft. |
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Effector |
If neuron signals to a gland or muscle rather than another neuron, this is the postsynaptic cell. |
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Reputake Carriers |
Bring neurotransmitters back into the presynaptic neuron. |
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Monosynaptic Reflex Arc |
A single synapse between the corresponding sensory neuron and motor neuron. Example is the knee-jerk reflex. |
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Polysynaptic Reflex Arc |
At least one interneuron between sensory and motor neurons. Example is withdrawal reflex (stepping on a nail). |
