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24 Cards in this Set
- Front
- Back
Action Potential
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A nerve impulse; a brief fluctuation in membrane potential caused by the rapid opening and closing of voltage-gated ion channels; also known as spike, nerve impulse, or discharge. Action potentials sweep like a wave along axons to transfer information from one place to another in a nervous system. The inside of the membrane is positive for a split second compared to the outside
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Excitable membrane
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Cells capable of generating and conducting action potentials- nerve and muscle cells- have this kind of membrane
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Resting Membrane Potential
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When a cell is not generating an impulse, the cytosol along the inside surface of the membrane has a negative electrical charge compared to the outside
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Ions
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Atoms or molecules with a net electrical charge
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Electrical current
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The movement of electric charge
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Electrical potential/voltage
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The force exerted on a charged particle
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Electrical conductance
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the relative ability of an electrical charge to migrate from one point to another
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electrical resistance
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the relative inability of an electrical charge to migrate
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Depolarization
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A change in membrane potential from the normal resting value (-65 mV) to a less negative value
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blood-brain barrier
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A specialization of the walls of brain capillaries that limits the movement of potassium into the extracellular fluid of the brain
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Ion Channels
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A membrane spanning protein that forms a pore that allows the passage of ions from one side of the membrane to the other
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Peptide Bonds
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Amino acids are assembled together where one the amino group of one amino acid is joined to the carboxyl group of the next
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Polypeptides
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Proteins made of a single chain of amino acids
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Ion selectivity
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a property of ion channels in the membrane that are selectively permeable to some ions and others not
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Gating
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a property of ion channels; channels with this property can be opened and closed
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Ion Pumps
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Enzymes that use the energy released by the breakdown of ATP to transport certain ions across the membrane
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Ohm's law
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I=gV, Current is the product of the conductance and the potential difference
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membrane potential
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the voltage across the neuronal membrane at any moment
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microelectrode
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a thin glass tube with an extremely fine tip that will penetrate the membrane of a neuron with minimal damage
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ionic equilibrium potential
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the electrical potential difference that exactly balances an ionic concentration gradient
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Nernst Equation
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The value of the equilibrium potential for any ion with this equation.
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Sodium-Potassium Pump
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An enzyme that breaks down ATP in the presence of internal Na+
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Calcium Pump
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An enzyme that actively transports Ca out of the cytosol across the cell membrane
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Goldman Equation
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A mathematical formula that takes into consideration the relative permeability of the membrane to different ions
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