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Frog Nerve

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1. How does a CAP differ from a single action potential?
Single action potentials follow the “all or none” rule. The “all or none” rule being that if a stimulus is strong enough to depolarize the membrane of the neuron to threshold, then an action potential will be fired. Each stimulus that reaches threshold will produce an action potential that is equal in magnitude to every other action potential for the neuron. Compound action potentials do not exhibit this property since they are a bundle of neurons and have different magnitudes of action potentials. Compound action potentials are also graded, meaning the greater the stimulus, the greater the action potential. 2. Action potentials are said to be all or none responses. Why does …show more content…

As you increase the amplitude, more neurons reach their threshold and contribute to the increase in size of the compound action potential (CAP). Eventually, as the stimulus voltage is increased, a point will be reached when the waveform of the action potential stops changing. At this point all the fibers in the nerve able to respond to the stimulus are stimulated, which is the maximal response. 4. In this exercise, you examined the effect of increasing stimulus intensity on the nerve. What other stimulus parameter might also affect the nerve's tendency to generate a CAP? 4. In this exercise, you examined the effect of increasing stimulus intensity on the nerve. What other stimulus parameter might also affect the nerve's tendency to generate a CAP?
Frequency and duration can also affect the nerve’s tendency to generate CAP’s. Frequency can affect it because if there is the right amount of time between them, their effects can be added and trigger a CAP. Durations can affect it because even a weak stimulus can potentially trigger a CAP if kept up long enough.
Exercise 2: Refractory Period 5. Explain the difference between the relative and absolute refractory periods.
During an absolute refractory period, a second stimulus will not produce a second action potential no matter how strong the stimulus is. Absolute refractory period corresponds to the period when Na+ channels are open (often just a millisecond or less). During a relative refractory period,

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