Physiology Answer 1
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Answer is 1. AccomodationFrom Ganong 19th Edition:
“The minimal intensity of stimulating current required to produce an action potential is known as Threshold intensity, the threshold intensity varies with duration; with weak stimuli it is long, and with strong stimuli it is short. Slowly rising currents fail to fire the nerve because the nerve adapts to the applied stimulus, a process called accommodation”
“Although sub threshold stimuli do not produce an action potential, they do have an effect on the membrane potential, Application of such currents with a cathode leads to a localized depolarizing potential that rises sharply & decays exponentially with time. Conversely, an anodal current produces a hyperpolarizing potential change of similar duration. These potential changes are called Electro tonic potentials, those produced at a cathode being called Cat electronic and those at an anode An electronic."
“During rising and much of the falling process of the spike potential, the neuron is refractory to stimulation.-this is called Refractory period, which is subdivided into *Absolute-period from the firing level is reached until re-polarization is about 1/3rd complete*Relative-lasting from this point to the start of after depolarization”
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Category: AIIMS Nov 2006 MCQs
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