PhysioEx Quiz 3 – Flashcards
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The typical concentration of sodium is _______?
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Lower than potassium intracellularly
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What effect does increasing the extracellular potassium have on the resting membrane potential?
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The resting membrane potential became less negative
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The channels that provide for the movement of potassium in the resting neuron are ______.
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Leakage
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Establishing the resting membrane potential requires energy through the use of the _____ .
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Sodium-potassium pump
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Which of the following describes a depolarization?
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The membrane becomes less polarized
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Which of the following does NOT describe graded potentials?
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They are always depolarizing
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When the intensity of the appropriate stimulus is increased, the amplitude of the response _____ .
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Increases
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We describe the regeneration of the action potential down the membrane of the axon of the neuron as _______ .
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Conduction or propagation
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The minimum voltage that is required to generate an action potential is called the ______ .
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Threshold voltage
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An axon that is more negative than the resting membrane potential is said to be _______ .
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Hyperpolarized
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If an increase in extracellular potassium hyperpolarizes a neuron, which of the following would be correct?
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It would change the membrane potential to a more negative value
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To reach threshold, the amount of sodium ______ .
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Entering the cell must overcome the potassium exiting
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Which of the following occurs first in the generation of an action potential?
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The membrane depolarizes
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Which of the following occurs during depolarization?
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Sodium flows into the cell
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Which of the following occurs during repolarization?
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Voltage-gated potassium channels open and some voltage-gated sodium channels inactivate. Potassium flows out of the cell
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Which of the following allow the movement of potassium through the neuronal membrane?
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Leakage channels and voltage-gated potassium channels
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Why does the threshold increase when the interval between the stimuli decreases?
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Some sodium channels have been inactivated and cannot be reopened immediately
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During the relative refractory period, ______ .
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Another action potential can be generated provided the stimulus is large enough
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When the stimulus intensity increases, _______ .
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The number of action potential increases
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The time interval between action potentials is called the _______
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Interspike interval
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During the relative refractory period, _________ .
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The stimulus must be above threshold to generate an action potential
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Which of the following is described correctly?
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Schwann cells provide the myelination in the PNS
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The rate with which an action potential travels along an axon ________ .
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Is called the conduction velocity and is measured in meters/sec
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The Nodes of Ranvier are _________ .
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Locations on the axon where the myelin sheath is absent
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The time interval for conduction would be shortest with ____________ .
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The largest and most heavily myelinated axons
