PhysioEx Lab Report
Exercise 3: Neurophysiology of Nerve Impulses Activity 5: The Action Potential: Measuring Its Absolute and Relative Refractory Periods Name: Sara Ross Date: 3 February 2023
Session ID: session-31361a5d-a1f6-9428-d386-9bcb40bbc417
Pre-lab Quiz Results
You scored 100% by answering 4 out of 4 questions correctly
1 Which of the following occurs after the peak of the action potential?
You correctly answered: All of these occur
2 What is meant by Na* channel inactivation?
You correctly answered: The Na* channel no longer allows Na*ions to pass through it
3 What happens when voltage-gated K* channels open?
You correctly answered: All of these occur.
4 It is harder to generate a second action potential soon after the first action potential because
You correctly answered: All of these make it harder to generate a second action potential.
Experiment Results Predict Question
1 Predict Question: If you further decrease the interval between the stimuli, will the threshold for the second action potential change?
depolarization).
Stop & Think Question
1 Threshold can be defined as the minimum voltage needed to generate an action potential. Is
the threshold for the first action potential the same as, or different from, the threshold for the second action potential with a 60 msec interval?
You correctly answered: The threshold for the first action potential is lower than the
threshold for the second action potential
Fxpntervar BetWeen Stimuli (msec) 250 125
Stimulus Voltage (mV)
Second Action Potential?
20 20 20 25 30 30 35 40 45 60 60 60
Yes Yes No No Yes No No No Yes Yes Yes No
60
60
60
30 30 30 30 15 7.5 3.75
Interval Between Stimuli = 250 msec Stimulus Voltage = 20 mV
100 70
60
00 100 200 300 400 500 600 700 800 9001000 Time (msec)
Interval Between Stimuli = 125 msec Stimulus Voltage = 20 mV
100
70
60 Stimulus (W) 100 200 300 400500600 700 800 900 1000 Time (msec)
Interval Between Stimuli = 60 msec Stimulus Voltage = 20 mV
100
70
60 Siuiius (mV) 100 200 300 400 500 600 700 800 900 1000 Time (msec)
Interval Between Stimuli = 60 msec Stimulus Voltage = 25 mV
100 70
60 Siuisus (mV) 100 200 300 400 500 600 700 800 900 1000 Time (msec)