+30 Neuron membrane potential (mV) B C -70 D The picture above represents an action potential in time. Match the physiological events below with the part of the action potential (identified A-D) when it occurs. Select "never happens" when appropriate. Note: some letters may be used more than once, while other letters may not be used at all. Select "never happens" when appropriate. Voltage-gated Nat channels are inactivated during this entire period K+ ions move into the cell, following their concentration gradient 1. A The cell is in a relative 2. B refractory period 3. C Most voltage-gated K+ channels are opened 4. D The cell becomes 5. Never happens depolarized An excitatory stimulus at the trigger zone could