Term
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Definition
| separation of charge across a membrane in all living cells due to unequal distribution of ions between the ECF and ICF |
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Term
| RMP (resting membrane potential) |
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Definition
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Term
| Anatomy of a nerve cell (neuron) |
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Definition
1. Soma (cell body)= nucleus, organelles
2. Dendrites= gather info into soma
3. Axon= carries AP away from soma
4. Axon hillock= site that determines if AP is generated or not
5. Colateral branching
6. Telodendria
7. Boutons= synaptic knobs; terminal ends
8. Schwann cells= myelin sheath
9. Nodes of Ranvier= non-myelinated axon |
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Term
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Definition
-permitted by myelinization
-an impulse down the axon
-"leap frog" over schwann cells on the nodes of ranvier |
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Term
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Definition
| a neuron either generates an AP or it does not |
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Term
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Definition
-saltatory conduction= 50x faster conduction rate
2 factors influence rate:
1.myelination= 50x faster
2.diameter of axon= the fatter diameter the faster conduction (50x faster) |
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Term
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Definition
| the body is breaking down myelin |
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Term
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Definition
1.Polarization(-70mV)= theres a separation of opposite charges
2.Depolarization(-60mV)=membrane potential is reduced moving to a more (+) inside
3.Repolarization(-70mV)=membrane returns to RMP after depolarization
4.Hyperpolarization(-80mV)=potential is greater than RMP - more (-) |
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Term
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Definition
-localized changes in membrane potential that can be depolarization or hyperpolarization (varying sizes or degrees of magnitude)
-spread by local current flow
-decremental=short-distance communication (decrease in strength/dies as it travels) |
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Term
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Definition
-"exitable membranes/tissues"= neurons and muscle cells
-brief, rapid reversals of membrane potentials
-spread by local current flow
-nondecremental= long-distance communication (as strong at bouton as at axon hillock) |
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Term
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Definition
electrical-->chemical-->electrical
1. AP arrives at nerve terminal
2.Na+ enteres and nerve boutons membrane depolarizes--Na+ innflux
3.Voltage-gated Ca++ channels open and influx of Ca++
4.Ca++ entry causes release of neurotransmitter from terminal--exocytosis into synaptic cleft
5.NTs bind to receptors in post-synaptic membrane
6.Binding of NT to receptor activates chemically gates ion channels |
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Term
| Inhibitory and Excitatory post-synaptic potentials |
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Definition
-changes in membrane potential on post-synaptic cell are graded
-synapses do not change--always either IPSP or EPSP
-EPSP= more(+); Na+ in
-IPSP= more(-); Cl- in or K+ out
-GPSP= sum of all info to reach axon hillock; EPSP+IPSP |
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Term
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Definition
1. Temporal= summation over time; more frequent; less time to relax
2.Spatial= summation over space; neurons activated at same time; 2 presynaptic charges add to "sum" |
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Term
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Definition
-neurotransmitter
-somatic neurons (skeletal)=excitatory
-autonomic neurons (involuntary)= excitatory or inhibitory |
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Term
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Definition
-muscarine; cardiac and smooth muscle
-G protein operated channel
-subunits=alpha, beta, gamma
-receptor but not a channel--> subunits activate another protein channel to open or close |
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Term
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Definition
-nicotine; skeletal, brain, autonomic ganglia
-ligand operated channel
-5 polypeptide subunits that form an ion channel
-2 subunits bind ACh to open channel |
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Term
| Acetylcholinesterase (AChE) |
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Definition
| membrane protein on postsynaptic neuron that inactivates ACh |
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Term
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Definition
-on brain stem
-regulates mood, behaviors, cerebral circulation
-not enough=depression |
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Term
| dopamine, epinephrine, and norepinephrine |
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Definition
-found in midbrain
-motor control-->limbic system (emotional reward out of wack) |
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Term
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Definition
- 80% glial
PNS:
1.Schwann Cells= myelin sheath; high rate of electrical ion movement/high AP rate
2.Satellite Cells=let out waste
CNS:
1.Oligodendrocytes=make myelin sheath in CNS
2.Microglia=carry on phagocytosis
3.Ependymal=choroid plexus-->produce CSF and circulate it through brain and spinal cord with cilia
4.Astrocytes=highest# & large star shaped
-nurse cells
-take up NTs after theyre released by
neuron
-cause formation of BBB
-formation of new neural synapses
-control ECF ion concentrations |
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Term
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Definition
1.sensory (afferent)=detect stimuli and transmit stimulus to the CNS
2.interneurons=lie w/in CNS; receive,interpret, and stimulate signals
3.motor(efferent)=send signals to muscles and gland cells from CNS |
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Term
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Definition
| receptor--> afferent neuron--> interneuron--> efferent neuron--> effector |
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