Lab Quiz

Neurophysiology and Nerve Impulses Lab Quiz

This activity contains 25 questions.

	Refer to Activity 1: Electrical Stimulation. When the nerve is stimulated at a voltage setting of 1.0 V, what is the response observed on the oscilloscope?   A small trace is observed. A large trace is observed. A steadily increasing trace is observed. A steadily decreasing trace is observed. There is no response.

	What is the threshold voltage?   1.0 V 1.5 V 2.0 V 2.5 V 3.0 V

	If the voltage is increased by 0.5, and Single Stimulus is clicked, how does this change the tracing?   A slight increase results. A sharp increase results. A slight decrease results. A sharp decrease results. No changes occur.

	The maximal voltage at which an increase in response is no longer observed is:   3.0 V 3.5 V 4.0 V 4.5 V 5.0 V

	Refer to Activity 2: Mechanical Stimulation. When the rod is positioned to touch the nerve, what do you see on the oscilloscope?   No response. An increase in the tracing. A decrease in the tracing.

	The response to the rod is indicative of which of the following conditions?   Multiple motor unit summation. Generation of an action potential. A stimulus too small to overcome threshold.

	How does the tracing (in response to the rod) compare to other tracings previously generated?   The tracing is identical to that observed below a threshold level. The tracing is identical to that observed generated at the threshold level. The tracing is greater than that observed generated at the threshold level.

	Refer to Activity 3: Thermal Stimulation. What happens when the heated rod is brought into contact with the nerve?   Nothing happens. An action potential is generated. The nerve is damaged.

	How does the tracing generated when the heated rod touches the nerve compare to the tracing you observed with the unheated rod?   It is slightly higher. It is significantly higher. It remains the same. It is slightly lower. It is significantly lower.

	Which of the following conclusions would you make, based on your experiments using the heated and unheated rods?   Thermal stimulation has no effect on generation of an action potential. Thermal stimulation has a negative effect on generation of an action potential. Thermal stimulation can cause the generation of an action potential.

	Refer to Activity 4: Chemical Stimulation. When a nerve is exposed to sodium chloride, is an action potential generated?   Yes No

	How does the tracing of the nerve exposed to sodium chloride differ from that of the original threshold stimulus tracing?   It is higher. It is lower. It is identical.

	What happens when the nerve is exposed to hydrochloric acid?   Nothing. An action potential is generated. The nerve is destroyed.

	How does the tracing of the nerve exposed to hydrochloric acid differ from that of the original threshold stimulus tracing?   There is no tracing due to nerve damage. It is higher. It is lower. It is identical.

	Based on your results, which type of stimuli were observed to elicit an action potential?   Electrical Chemical Mechanical Thermal All of the above.

	Refer to Activity 5: Testing the Effects of Ether. How would you describe the trace that is generated when the nerve is exposed to ether?   The trace is identical to that at threshold level. The trace is lower than that at threshold level. The trace is higher than that at threshold level. The trace is a flat line.

	What was the effect of ether on the nerve?   It was stimulatory. It was inhibitory. It had no effect.

	How long does it take the nerve to return to normal?   1 minute. 2 minutes. 4 minutes. 5 minutes. 8 minutes. 10 minutes.

	Refer to Activity 6: Testing the Effects of Curare. What was the effect of curare on the action potential?   It was stimulatory. It was inhibitory. It had no effect.

	How would you explain the effect of curare on the action potential?   Curare lowers the threshold level. Curare increases the threshold level. Curare affects the synapse rather than nerve propagation; therefore it had no effect on the action potential.

	Refer to Activity 7: Testing the Effect of Lidocaine. What happens when lidocaine is applied to the nerve and the nerve is stimulated at the threshold level?   An action potential is generated that is identical to the original trace. An action potential greater that the original trace is generated. An action potential smaller than the original trace is generated. The trace is a flat line.

	At what level of the nerve does lidocaine have its effect?   It blocks transmission at the synapse. It increases the threshold level of the nerve. It decreases the threshold level of the nerve. It blocks sodium ion channels from opening, inhibiting action potentials. It blocks potassium ion channels from opening, inhibiting action potentials.

	Refer to Activity 8: Measuring Nerve Conduction Velocity. Of the four nerves tested, which had the slowest conduction velocity?   The earthworm The frog Rat nerve #1 Rat nerve #2 They were all equal in conduction velocity.

	Based on your results, what can you infer about nerve size and conduction velocity?   The smaller the nerve, the faster the conduction velocity. The larger the nerve, the faster the conduction velocity. The larger the nerve, the slower the conduction velocity. The nerve size has no effect on conduction velocity.

	Which of the following is true?   All other factors equal, an unmyelinated nerve has a faster conduction velocity than a myelinated nerve. There is no difference in the conduction velocity of a myelinated nerve versus an unmyelinated nerve. All other factors equal, a myelinated nerve has a faster conduction velocity than an unmyelinated nerve.

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