GENERAL ANATOMY
NERVOUS SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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This is the largest charge achieved during an action potential
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This is the threshold required to complete an action potential
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This is the resting charge of a neuron
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This is the charge when all the sodium is inside the cell
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Detailed explanation-1: -This means that some event (a stimulus) causes the resting potential to move toward 0 mV. When the depolarization reaches about-55 mV a neuron will fire an action potential. This is the threshold. If the neuron does not reach this critical threshold level, then no action potential will fire.
Detailed explanation-2: -In electrophysiology, the threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential. In neuroscience, threshold potentials are necessary to regulate and propagate signaling in both the central nervous system (CNS) and the peripheral nervous system (PNS).
Detailed explanation-3: -The threshold potential for most excitable cells is about 15 mV less negative than the resting membrane potential. In a nerve, if the membrane potential decreases from-70 mV to-55 mV the cell fires an action potential which propagates along the axon.
Detailed explanation-4: -For example, the threshold value for a typical neuron is near-55 mV, while the resting membrane potential is near-70 mV. If a graded potential is not sufficient to bring the membrane up to the threshold value (-55 mV), then an action potential cannot be initiated.
Detailed explanation-5: -Threshold is the minimum current required for the cell membrane to generate an action potential. True. For an action potential to happen, a local potential must rise to a critical voltage called the threshold (typically about-55 mV)-the minimum needed to open voltage-gated channels.