Physioex Cd Exercise 3 Nervous

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Eliciting (Generating) a Nerve Impulse

1.Why don’t the terms depolarization and action potential mean the same thing? Depolarization has to do with surfaces becoming more negative or positive and reaches a certain point called a threshold. When the threshold is reached, an action potential is initiated.

2.What was the threshold voltage in Activity 1?
The threshold voltage in Activity 1 was 3.0.

3.What was the effect of increasing the voltage? How does this change correlate to changes in the nerve? There was little change in effect of increasing the voltage. The action potential increased slightly. There was a small increase in the repolarization and a slightly lower resting potential.

4.How did the action potential generated with the unheated rod compare to that generated with the heated rod? The action potential generated with the unheated rod was similar to that generated with the heated rod. The heated rod made a slightly larger action potential than the unheated rod.

5.Describe the types of stimuli that generated an action potential. The different stimuli that generate an action potential are electrical, chemical, mechanical, and thermal.

6.If you were to spend a lot of time studying nerve physiology in the laboratory, what type of stimulus would you use and why? I would use chemical stimulation. I would want to see what different chemicals would cause an action potential versus chemicals that would not cause an action potential. And, whether different amounts of a particular chemical would affect the action potential.

7.Why does the addition of sodium chloride elicit an action potential? Hint: Think about the sodium permeability of the neuron (Figure 3.2e). The addition of sodium chloride will increase the sodium ion concentration outside the cell membrane. The sodium channels will open allowing sodium ions to enter the cell in hopes of equilibrium (depolarization). The cell will balance this polarity and pump...
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