BIOLOGICAL BASES OF BEHAVIOR
NEUROTRANSMISSION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Negatively charged sodium ions rush out of ion channels and positively charged potassium ions rush in.
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Positively charged sodium ions rush out of ion channels and negatively charged potassium ions rush in
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Positively charged sodium ions rush in to ion channels and negatively charged potassium ions rush out.
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None of the above
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Detailed explanation-1: -Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron. Remember, sodium has a positive charge, so the neuron becomes more positive and becomes depolarized.
Detailed explanation-2: -If you are alert, you notice that both the sodium and the potassium ions are positive. Neurons actually have a pretty strong negative charge inside them, in contrast to a positive charge outside. This is due to other molecules called anions. They are negatively charged, but are way too big to leave through any channel.
Detailed explanation-3: -Moreover, K+ is a positively charged ion that has an intracellular concentration of 120 mM, an extracellular concentration of 4 mM, and an equilibrium potential of-90 mV; this means that K+ will be in electrochemical equilibrium when the cell is 90 mV lower than the extracellular environment.
Detailed explanation-4: -The resting membrane potential of a neuron is about-70 mV (mV=millivolt)-this means that the inside of the neuron is 70 mV less than the outside. At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.