BIOL 240W: EXAM 3.2
39 Cards in this Set
| Front | Back |
|---|---|
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Amitotic
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unable to divide
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Nerve cell lifetime
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over 100 years
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Nuclei
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clusters of cell bodies in CNS
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Ganglia
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cluster of cell bodies in PNS
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Tracts
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bundles of axons in CNS
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Nerves
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bundles of axons in PNS
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Post synaptic cell
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cell that revives a signal
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Glial cell functions
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nourishing, insulating and extracellular fluid removal
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Resting potential
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nontransmitting negative potential
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Na/K pump
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ATP used to pump 3Na out for 2K in
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Which solute is more permeable
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Potassium
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Resting potential theory
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Chemical gradient balances with electrical gradient
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Which solute is most responsible for the nerve cell gradient
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Potassium (-90mV)
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Abundance of leak channels
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Higher # of potassium leak channels
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Gated ion channels
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open or close in response to a stimulus(polerization or neurotransmitter)
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Hyperpolarization
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makes resting potential more negative, harder to create a signal
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Depolarization
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makes resting potential more positive, Easier to create a signal
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Graded potential
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potential strength changes around strength of stimuli
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Voltage-gated ion channels
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open and close based on change of membrane potential
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-55mV
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threshold of action potential
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-70mV
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average resting potential
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-90mV
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K+ only potential
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+62mV
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Na+ only potential
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Resting State
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all vGated channels closed
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Inactivation Loop
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blocks sodium from flowing into cell
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Rising Phase
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when threshold is crossed, Activation of Na+ gated channels begins unassisted
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Why is E(Na) potntial not reached
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B/c potassium begins to leave the cell
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Why is resting potential overshot
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Because Na channels are slow to respond
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Why do action potentials travel unidirectionally
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Because of the hyperpolarization "behind" the wave
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Myelination
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prevents signal leakage and allows saltatory conduction
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jumping of signals from node to node on axon
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jumping of signals from node to node on axon
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Wider axons
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faster signal propegation
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Oligodendrocytes
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mylin laying cells in CNS
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Schwann Cells
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mylin laying cells in PNS
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Electrical Synapses
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quickens cell to cell communication, seen in cardiac tissue
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Chemical Synapses
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neurotransmitters released by presynaptic cells
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Ending neurotransmitter transmisson
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uptake by presynaptic cell, metabolized by glial cells, metabolized by an enzyme, diffusion
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EPSPs IPSPs
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excitsory And inhibitory nurotrans signal
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Neural Integration
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addition of EPSPs can push a neuron over threshold
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BIOL 240W: EXAM 2.4