Action potentials (nerve impulses) are changes in the membrane potential that, once started, will affect the entire excitable membrane. the first action potential is usually generated at the initial segment of the neuron's axon. this activity will test your understanding of the sequence of events that occur at the membrane of the initial segment of the axon during generation of an action potential. place the events involved in generation of an action potential in the correct order of occurrence from left to right. 1.k+ effluxrepolarization2.na+ channels closek+ channels open3.hyperpolarization k+ channels close4.threshold stimulus na+ channels open5.na+ influx depolarization