Human Anatomy and Physiology : Help with Action Potential Physiology
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Example Questions
Example Question #11 : Help With Action Potential Physiology
A stimulus applied to a neuronal membrane that causes its potential to become more positive is __________. A stimulus that moves the potential closer to 0 is __________.
hyperpolarization . . . resting membrane potential
hyperpolarization . . . hyperpolarization
hyperpolarization . . . depolarization
depolarization . . . depolarization
depolarization . . . hyperpolarization
hyperpolarization . . . depolarization
If an already positive membrane potential becomes more positive, it is becoming hyperpolarized because the electrical difference between the inside and outside of the cell is getting larger. On the other hand, a stimulus that moves the potential difference closer to 0 is depolarizing because it is decreasing the difference in electrical potential between the inside and outside of the cell.
Example Question #12 : Neural Physiology
The presence of __________ dramatically increases the speed at which an action potential moves along an axon.
neurilemma
plasma protein
myelin
a capsule
myelin
Myelin helps to increase resistance along the axon, which helps to propagate the action potential along the axon.
Example Question #12 : Neural Physiology
The following are the main steps in the generation of an action potential:
1. inactivation of Na channels and activation of K channels
2. depolarization to threshold
3. return to normal permeability
4. activation of Na channels
What is the proper sequence of these events?
2,4,3,1
4,3,2,1
2,4,1,3
1,2,3,4
2,4,1,3
In order to have an action potential, you must have a depolarization. Na channels must close before K channels open
Example Question #14 : Neural Physiology
Which part of the neuron generates the action potential?
axon
dendrites
nucleus
cell body
axon hillock
axon hillock
The action potential of a neuron is generate at the axon hillock and is propagated down the axon and to the terminal branches where it will synapse with the dendrites of the next neuron.
Example Question #13 : Neural Physiology
Which of the following describes the influx of 
none of these
hyperpolarization
polarization
depolarization
repolarization
depolarization
The influx of positive sodium ions into the neuron is known as depolarization. This is the loss of negative charge that occurs when positive sodium passes through the neural membrane and enters the neuron.
Example Question #14 : Neural Physiology
When the neuron becomes depolarized, which of the following events takes place?
influx of sodium ions
efflux of potassium ions
None of these will occur.
influx of potassium ions
efflux of sodium ions
influx of sodium ions
Depolarization is when the neuron becomes more positive by gaining positively charged ions, specifically sodium ions. During depolarization the sodium ion channels open and sodium ions enter the neuron, reducing the membrane potential to roughly +35 mV.
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