MATH 246 Quiz: Quiz 2 Solutions Spring 2009

• School: University of Maryland
• Department: Mathematics
• Course: MATH 246
• Professor: All

Document Summary

Nervous system i 2009 exam 1 key: two refractory periods occur during the time course of an action potential, identify the two refractory periods and the membrane elements (channel or gate to a channel) responsible for each. It is the added conductance of k+, brought on by the continued open state of voltage-gated k+ channels, that accounts for the relative refractory period. Absolute = inactivation gates of voltage-gated na+ channels. Relative refractory period would we weaker because it would fail to reach normal hyperpolarizing potential, simply because the outward driving force for k+ would be reduced by 17 mv. There is no advantage to that effect for a neuron, however, and we know it occurs as an addition to the real benefit of that refractory period. The absolute refractory period keeps action potentials uni-directional. Many of you phrased this as preventing back-propagation.