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Cards In This Set
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Action Potential
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 Brief fluctuation in membrane potential caused by the rapid opening and closing of voltage gated ion channels; AKA spike, nerve impulse or discharge. |
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Excitable Membrane
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Any membrane capable of generating action potentials (ex: axons and muscle cells are excitable)
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Resting Membrane Potential
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Membrane voltage maintained by a cell when it is not generating action potential. Neurons have resting potential of about -65mV
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Ion Channels
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 Membrane-spanning protein that forms a pore that allows the passage of ions from one side of the membrane to another |
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Ion Pumps
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 A protein that transports ions across the membrane at the expense of metabolic energy (ATP) |
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Electrical Current
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Movement of electrical charge; measured in amperes and represented by the letter I
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Electrical Potential
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AKA as voltage; measures the force exerted on a charged particle; also measures the difference in charge between the anion and the cation
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Electrical Conductance
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Relative abilty of an electrical charge to migrate from one point to another. it is measured in siemens and represented by the letter g
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Electrical Resistance
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Relative inability of an electrical charge to migrate. Represented by the symbol R, measured in ohms. (inverse of conductance)
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Ohm's Law
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I=gV
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Membrane Potential
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Voltage across the neuronal membrane at any moment, reresented by the symbol V(m). Can be measured by inserting a microelectrode into the cytosol
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Equilibrium Potential
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Electrical potential difference that exactly balances an ionic concentration gradient; represented by E(ion)
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Ionic Driving Force
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=V(m)-E(ion)
Difference between the real membrane potential and the equilibrium potential
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Bloood-Brain Barrier
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Specialixation of the walls of brain capillaries that limits the movement of bloodborne substances into the extracellular fluid of the brain
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Threshold
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The critical level of depolarization that must be crossed in order to trigger an action potential
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