p.36 Activity 1 1. Explain why the resting membrane potential had the same value in the cell body and the axon. 2. Describe what would happen to a resting membrane potential if the sodium-potassium transport pump was blocked. 3.Describe what would happen to a resting membrane potential if the concentration of large intracellular anions that are unable to cross the membrane is experimentally increased.
p.38-39 Activity 2 1.Are graded receptor potentials always depolarizing?Do graded receptor potentials always make it easier to induce action potentials? 2. Based on the definition of membrane depolarizationin this activity,define membrane hyperpolarization. 3.What do you think is the adequate stimulusthat would inappropriately activate the sensory receptors in the ear if the stimulus had enough intensity?
p.40Activity 3 1.Explain why the threshold voltage is not always the same value (between axons and within an axon). 2.Describe how the action potential is regenerated by local ion flux at each location on the axon. 3.Why doesn't the peak value of the action potential increase with stronger stimuli?
p.42 Activity 4 1. If depolarizing membrane potentials open voltage-gated sodium channels,what closes them? 2. Why must a sushi chef go through years of training to prepare puffer fish for human consumption? 3. For action potential generation and propagation, are there any other cation channels that could substitute for the voltage-gated sodium channels if the sodium channels were blocked?
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