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29 Cards in this Set
- Front
- Back
What makes myelin in the CNS? |
Ogliodendrocytes |
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What makes myelin in PNS |
Schwann Cells |
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What components make up a synapse? |
nerve terminal, synaptic cleft, and postsynaptic membrane |
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Nerve |
multiple neurons bundled together in the PNS |
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3 types of PNS nerves? |
sensory, motor, mixed |
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What is a ganglia |
Found in the PNS. They are the cell bodies of neurons of the same type clustered together |
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tracts |
In the CNS axons are bundled into tracts. Unlike nerves they only carry one type of info. |
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nuclei |
The cell bodies of the neurons in the same tract are grouped in nuclei |
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gllial cells, or neuroglia cells |
structural and supportive role |
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astrocytes |
nourish neurons and form the blood brain barrier which controls the transmission of solutes from the bloodstream to the nervous tissue |
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ependymal cells |
line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber |
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microglia |
phagocytic cells that ingest and break down waste products and pathogens in the CNS |
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action potential |
all or nothing signals in a neuron |
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resting membrane potential |
-70 mV on the inside of the neuron, maintained by the sodium/potassium pump |
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Na/K pump |
pumps three sodium ions out of the cell for every two K ions pumped in |
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temporal summation |
refers to the addition of multiple signals near each other in space |
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spatial summation |
refers to the addition of multiple signals near each other in space |
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what is the threshold voltage? |
-50 Mv |
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What happens to sodium? |
Sodium flows into the cell when it becomes depolarized, raising the the action potential at +35 the na channels inactivate |
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What happens to K |
Potassium channels open when the action potential reach +35 mV, and K flows out of the cell -- and repolarizes it |
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absolute refractory period |
cell cannot fire another action potential |
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relative refractory period |
cell can fire, but it needs a stronger than normal signal to cause it . |
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3 ways that neurotransmitters are removed from the synapse? |
1. broken down 2. taken back up 3. diffuse out |
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White matter |
myelinated axons in the brain white matter is deeper than gray this is reversed in the spinal cord |
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gray matter |
unmyelinated axons |
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Two divisions of the PNS |
1. somatic 2. autonomic
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reflex arcs |
use the ability of interneurons in the spinal cord to relay information to the source of the stimuli while also routing it to the brain |
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monosynaptic reflex arc |
the sensory neurons fires directly on the motor neuron |
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polysynaptic reflex arc |
the sensory neuron may fire onto a motor neuron as well as interneurons that fire onto other motor neurons. Ex. withdrawal reflex |