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18 Cards in this Set
- Front
- Back
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What are the 2 phases of Action Potential
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Depolarization
Repolarization |
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When does Depolarization occur
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When the inside of the plasma membrane becomes less negative
Caused by the stimulation of a cell Triggers an action potential if the membrane potential reaches value threshold |
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What is the Depolarization Phase
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A brief period during which further depolarization occurs and the inside of the cell becomes positively charged
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When does Repolarization occur
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When the membrane potential moves from its maximum degree of depolarization toward the value of resting membrane potential
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What is the Repolarization Phase
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The return of the membrane potential to its resting value
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What results in Depolarization and Repolarization
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The opening and closing of voltage gated ion channels changing the permeability of the plasma membrane to ions
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When does Action Potential end and the Resting Membrane Potential restablish
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When the Voltage Gated K+ channels close
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What is the "all" in the all or none principal
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When the stimulus has enough strength to produce a depolarization that reaches threshold or exceeds threshold, ALL of the permeability changes responsible for an action potential proceeds without stopping
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What is the "none" in the all or none principal
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When the stimulus doesn't have enough strength to reach threshold - the membrane potential returns to its resting level without producing an action potential
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What is Propagate
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The ability for an action potential to travel across the plasma membrane - although the action potential doesn't actually move, the causes the stimulation of another action potential in an adjacent location
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What is the Action Potential Frequency
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The number of Action Potential produced per unit of time - The Action Potential Cell Frequency Increases as the Strength of the Stimulus Increases
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What is the Presynaptic Terminal
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The location of the Voltage Gated Ca+ Channel at each Axon Terminal
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What is the Synaptic Cleft
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The space between the Presynaptic Terminal the and Muscle Fiber / Postsynaptic Membrane
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What is the Postsynaptic Membrane / Motor End Plate
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The location of the Ligand Gated Na+ Channel - The area of the junction of the muscle plasma membrane
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What is the Synaptic Vesicle
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Spherical Sacs that contain Acetylcholine
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What is Acetylcholine
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An organic material composed of acetic acid and choline - Acts as a Neurotransmitter - Broken down by the enzyme Acetylcholinesterase
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What is a Neurotransmitter
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A substance released from a presynaptic membrane that diffuses across the synaptic cleft and stimulates (or inhibits) the production of an action potential in the postsynaptic membrane
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What is an Acetylcholinesterase
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An enzyme that breaks down acetylcholine - Prevents the accumulation of acetylcholine within the synaptic cleft
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