Unit 9 Assignment SC121

LABORATORY REPORT
Activity:

Action Potentials

Name:

Barbara Uthe

Instructor:

Catherine Rice

Date:

08.17.2014

Predictions
Exceeding threshold depolarization at the trigger zone______the likelihood of generation of an action potential. increases Action potential amplitude increases with distance
Increasing frequency of stimulation to the trigger zone decreases number of action potentials

Materials and Methods
Experiment 1: Effect of Stimulus Strength on Action Potential Generation
Dependent Variable membrane potential
Independent Variable stimulus strength (voltage)
Controlled Variables frequency of stimulation, type of neuron

Experiment 2: Effect of Frequency of Stimulation on Action Potential Generation
Dependent Variable membrane potential
Independent Variable frequency of stimulation
Controlled Variables stimulus strength (voltage), type of neuron

1. Which part of the neuron was stimulated?
Axon
2. Where was membrane potential measured?
Axon Hillock
3. What was used to measure membrane potential? stimulus strength (voltage)

Results
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
Axon hillock
Axon

0 V (no stimulation )
-68.6
-68.5

2V
-63.6
-73

Stimulation Voltage
4V
-56.1
-64.4

Laboratory Report/ Barbara Uthe/ Action Potentials/ Catherine Rice/ 08.17.2014/ Page [1] of [4]

6V
30
30.4

8V
30
-68.5

b. Action Potential Generation.
Location

Action potential generated?
Difference in action potential amplitude with distance Stimulation voltage
4V
6V

0 V (no stimulation )
No

2V

8V

No

No

Yes

Yes

-00.10

9.40

8.30

-.40

98.5

Graph 1. Maximal depolarization of membrane potential at axon hillock and axon after different stimulation voltages.

Resting membrane potential = -70