University:
American Career College
Course:
NURS112 | Fundamentals of Nursing
Academic year:

2022
Views:

381

Pages:

4
Author:

Braiden Lam

Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 Axons are You correctly answered: long, thin structures that extend from a neuronal cell body. 2 Which of the following is easier? You correctly answered: Extracellular recordings of the action potential. 3 An action potential is usually initiated in an axon at or near You correctly answered: all of the above. 4 The initiation of an action potential in a sensory neuron in the body normally You correctly answered: follows a suﬃciently large depolarizing receptor potential. Experiment Results Predict Question 1 Predict Question: How will the action potential at R1 (or R2) change as you continue to increase the stimulus voltage? Your answer: The peak value of the action potential will increase. Stop & Think Questions 1 Why is the action potential recorded by the second recording electrode (R2) delayed relative to the action potential recorded by the ﬁrst recording electrode (R1)? You correctly answered: The action potential had to propagate from R1 to R2. + 2 An increase in extracellular K would depolarize a neuron. This depolarization would occur if neurons were damaged. From what you have just learned about generating an action potential, what eﬀect would this have on nearby axons? The nearby axonal membranes will _______. You correctly answered: be depolarized to values near or above threshold voltages. Experiment Data Stimulus Voltage (mv) 10 Peak Value at R1 (μV) Peak Value at R2 (μV) 0 0 Action Potential No 20 100 100 Yes 30 100 100 Yes 40 100 100 Yes 50 100 100 Yes Post-lab Quiz Results You scored 100% by answering 3 out of 3 questions correctly. 1 The threshold voltage in an axon is usually You correctly answered: less negative than the resting membrane potential. 2 If a graded receptor potential made the resting membrane potential of the axon more negative (for example, -70 mV changes to -75 mV), you would expect You correctly answered: it to be more diﬃcult for this axon to reach the threshold voltage. 3 Failure to reach the threshold voltage in the axon of a sensory neuron could be caused by You correctly answered: all of the above. Review Sheet Results 1 Deﬁne the term threshold as it applies to an action potential. Your answer: Only when potential reaches to threshold, action potential can occur. 2 What change in membrane potential (depolarization or hyperpolarization) triggers an action potential? Your answer: Depolarization is the trigger of action potential. 3 How did the action potential at R1 (or R2) change as you increased the stimulus voltage above the threshold voltage? How well did the results compare with your prediction? Your answer: Action potential didn't change as the stimulus voltage increased. Threshold is the only point and action potential is ﬁxed whenever it occurs. 4 An action potential is an "all-or-nothing" event. Explain what is meant by this phrase Your answer: It occurs or does not. When it occurs its potential value is always same. 5 What part of a neuron was investigated in this activity? Your answer: The axon.