Task 5 - 3report_potentials.pdf
Exceeding threshold depolarization at the trigger zone______the likelihood of generation of an action potential.
Action potential amplitude
does not change with distance
Increasing frequency of stimulation to the trigger zone
does not change number of action potentials.
Materials and Methods
Experiment 1: Effect of Stimulus Strength on Action Potential Generation
stimulus strength (voltage)
frequency of stimulation, type of neuron
Experiment 2: Effect of Frequency of Stimulation on Action Potential Generation
frequency of stimulation
stimulus strength (voltage), type of neuron
1. Which part of the neuron was stimulated?
2. Where was membrane potential measured?
3. What was used to measure membrane potential?
voltmeter, patch clamp equipment and electrodes
Table 3: Membrane Potentials at Different Stimulation Voltages, by Location.
a. Values of maximal depolarization of membrane potential (mV) at different stimulation voltages, by location.
Location Stimulation Voltage
0 V (no stimulation ) 2 V 4 V 6 V 8 V
Axon hillock -68 -63.2 -55.7 29.9 30.6
Axon -67.6 -72.6 -63.9 29.8 -67.6
b. Action Potential Generation.
Location Stimulation voltage
0 V (no
2 V 4 V 6 V 8 V
NO NO NO YES YES
-0.4 9.4 8.2 0.1 98.2
Graph 1. Maximal depolarization of membrane potential at axon hillock and axon after different
Resting membrane potential = -70 mV.
1. What was the resting membrane potential (no stimulation) recorded in Table 3?
-68 at Axon Hillock and 67.6 at Axon
2. At which stimulation voltage(s) did you see decrimental conduction of graded potential...