Exercise 3: Neurophysiology of Nerve Impulses Worksheet
Eliciting a Nerve Impulse
Activity 1: Electrical Stimulation
Do you see any kind of response on the oscilloscope screen? No there was no response, the line was flat 2.
What was the threshold voltage, or the voltage at which you first saw an action potential? 3.0V 3.
How does this tracing compare to the one that was generated at the threshold voltage? At 3.5V the high & low peaks were just slightly above and below respectively the tracing that occurred at 3.0V 4.
What reason can you give for the change? An increase in the voltage can cause an increase in the peaks on the tracing because it is most likely leading to all of the nerve fibers firing 5.
Record this maximal voltage here: 4.0V
Activity 2: Mechanical Stimulation
When the glass rod is touching the nerve, what do you see on the oscilloscope screen? When the glass rod touches the nerve an action potential occurs 2.
How does this tracing compare with the other tracings you have generated? With the glass rod touching the nerve the tracing matches the tracing at 3.0V
Activity 3: Thermal Stimulation
What happens when the heated rod touches the nerve? When the heated glass rod touched the nerve and action potential occurs 2.
How does this trace compare to the trace that was generated with the unheated glass bar? The tracing from the heated glass rod has peaks high & low that are higher & lower respectively than the tracing of the nerve being touched with the non heated glass rod 3.
What explanation can you provide for this? That the nerve can be stimulated with heat
Activity 4: Chemical Stimulation
Does the sodium chloride generate an action potential? The sodium chloride does generate an action potential 2.
Does this tracing differ from the original threshold stimulus tracing? No If so, how? 3.
Does the hydrochloric acid generate an action potential? The hydrochloric acid does generate an action potential...
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