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. describe how does this tracing compare with the other tracings you have generated?
Activity 3- Thermal Stimulation
1. describe what happens when the heated rod touches the nerve?
2. describe how does this trace compare to the trace that was generated with the unheated glass bar?
3. describe what explanation can you provide for this?
Activity 4- Chemical Stimulation
1. describe does the sodium chloride generate an action potential?
2. describe does this tracing differ from the original threshold stimulus tracing? If so, how?
3. describe does the hydrochloric acid generate an action potential?
4. describe 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. describe what sort of trace do you see?
2. describe what has happened to the nerve?
3. describe How long does it take for the nerve to return to normal?
Activity 6- Testing the Effects of Curare
1. describe does this generate an action potential?
2. describe what describes this effect?
3. describe 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. describe which nerve in the group has the slowest conduction velocity?
2. describe what was the speed of the nerve?
3. describe which nerve of the four has the fastest conduction velocity?
4. describe what was the speed of the nerve?
5. describe what is the relationship between nerve size and conduction velocity? What are the physiological reasons for this relationship?
6. describe 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. describe what are the evolutionary advantages achieved by the myelination of neurons?