NSCI 175 Exam 1- Action Potential
Threshold - Answer-the critical level of depolarization that must be reached in order to trigger an action
potential
Rising phase - Answer-rapid depolarization of the membrane, continues until Vm= 40 mV
Peak - Answer-when the membrane reaches 30 mV, which causes gated sodium channels to close and
potassium channels to open
Falling Phase - Answer-a rapid repolarization until the inside of the neuron is positively charged with
respect to the outside
Afterhypolerization - Answer-when the repolarization causes the inside to be more negative than
resting potential
Refractory period - Answer-limit to the rate at which a neuron can fire an AP
Absolute refractory period - Answer-impossible to initiate another action potential once one has been
initiated for about one msec
Threshold - Answer-the critical level of depolarization that must be reached in order to trigger an action
potential
Rising phase - Answer-rapid depolarization of the membrane, continues until Vm= 40 mV
Peak - Answer-when the membrane reaches 30 mV, which causes gated sodium channels to close and
potassium channels to open
Falling Phase - Answer-a rapid repolarization until the inside of the neuron is positively charged with
respect to the outside
Afterhypolerization - Answer-when the repolarization causes the inside to be more negative than
resting potential
Refractory period - Answer-limit to the rate at which a neuron can fire an AP
Absolute refractory period - Answer-impossible to initiate another action potential once one has been
initiated for about one msec
