Label in detail the process of eliciting a nerve impulse.
Eliciting a Nerve Impulse
Activity 1- Electrical Stimulation
1. Do you see any types of response on the oscilloscope screen?
2. What was the threshold voltage or else the voltage at which you first saw an action potential? V
3. How does this tracing associate to the one that was generated at the threshold voltage?
4. What cause can you give for the change?
5. Record this maximal voltage here- V
Activity 2- Mechanical Stimulation
1. When the glass rod is touching the nerve and what do you see on the oscilloscope screen?
2. Explain how does this tracing compare with the other tracings you have generated?
Activity 3- Thermal Stimulation
1. Explain what happens when the heated rod touches the nerve?
2. Explain how does this trace compare to the trace that was generated with the unheated glass bar?
3. Explain what explanation can you provide for this?
Activity 4- Chemical Stimulation
1. Explain does the sodium chloride generate an action potential?
2. Explain does this tracing differ from the original threshold stimulus tracing? If so, how?
3. Explain does the hydrochloric acid generate an action potential?
4. Explain does this tracing differ from the original threshold stimulus tracing? If so, how?
5. How to summarize your experimental results, what kinds of stimuli can elicit an action potential?
Inhibiting a Nerve Impulse
Activity 5- Testing the Effects of Ether
1. Explain what sort of trace do you see?
2. Explain what has happened to the nerve?
3. Explain How long does it take for the nerve to return to normal?
Activity 6- Testing the Effects of Curare
1. Explain does this generate an action potential?
2. Explain what explains this effect?
3. Explain what do you think would be the overall effect of Curare on the organism?
Activity 7 Testing the Effects of Lidocaine
1. How does this generate a trace?
2. What sort of tracing is seen at the threshold voltage?
3. Why does Lidocaine have this effect on nerve fibre transmission?
Nerve Conduction Velocity
Activity 8- Measuring Nerve Conduction Velocity
1. Explain which nerve in the group has the slowest conduction velocity?
2. Explain what was the speed of the nerve?
3. Explain which nerve of the four has the fastest conduction velocity?
4. Explain what was the speed of the nerve?
5. Explain what is the relationship between nerve size and conduction velocity? What are the physiological reasons for this relationship?
6. Explain Based on the results, what is your supposition regarding the effects of myelination on conduction velocity and what are the physiological reasons for your conclusion?
7. Explain what are the evolutionary advantages achieved by the myelination of neurons?