Frog Nerve. Exercise 1: Determination of threshold voltage and maximal CAP amplitude. Study Questions. Exercise 2: Determination of the refractory period. Study Questions

Frog Nerve

Exercise 1: Determination of threshold voltage and maximal CAP amplitude

Using the Horizontal Compression buttons, display the data for Exercise 1 you wish to include in your report.

Nerve Threshold
Stimulus (mV)	CAP (mV)

Study Questions

1. How does a CAP differ from a single action potential?

2. Action potentials are said to be all or none responses. Why does the frog sciatic nerve give a graded response?

3. What was the smallest voltage required to produce the maximum (largest) CAP? What proportion of the nerve fibers were excited to produce this maximal response?

4. In this exercise, you examined the effect of increasing stimulus intensity on the nerve. What other stimulus parameter might also affect the nerve's tendency to generate a CAP?

Exercise 2: Determination of the refractory period

Using the Horizontal Compression buttons, display the data for Exercise 2 you wish to include in your report.

Refractory Period
Stimulus Interval (ms)	Amplitude 2nd CAP (mV)
4.0
3.5
3.0
2.5
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0

Study Questions

1. Explain the difference between the relative and absolute refractory periods.

2. Briefly describe the cellular events responsible for the refractory period. (Hint: Discuss the mechanism of repolarization).

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