Activity 5: Testing the Effects of Ether
*What sort of trace do you see when you click stimulate, using the voltage setting from the threshold stimulus you used in the earlier activities?
*What has happened to the nerve?
*How long does it take for the nerve to return to normal?
Activity 6: Testing the Effects of Curare
*Does this generate an action potential when you set the stimulator at the threshold voltage setting from activity 1 and stimulate the nerve?
*What explains this effect?
*What do you think would be the overall effect of curare on the organism?
Activity 7: Testing the Effects of Lidocaine
*Does this generate a trace when you drag the dropper from the bottle marked lidocaine, and position it over the nerve, between the stimulating and recording electrodes. release the drops so they can dispense?
*Stimulate the nerve at the threshold voltage. What sort of tracing is seen?
*Why does lidocaine have this effect on the nerve friber transmission?
Activity 8: Measuring Nerve Conduction Velocity
*Do you see an action potential? If not, increase the voltage by increments of 1.0V until a trace is obtained. At what threshold voltage do you 1st see an action potential generate?______V
*Which nerve in the group has the slowest conduction velocity?
*What was the speed of the nerve?
*Which nerve of the four has the fastest conduction velocity?
*What was the speed of the nerve?
*What is the relationship between nerve size and conduction velocity? What are the physiological reasons for this relationship?
*Based on the results, what is your conclusion regarding the effects of myelination on conduction velocity? What are the physiological reasons for your conclusion?
*What are the evolutionary advantages achieved by the myelination of neurons?
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