What is the action potential?
Keep in mind that the action potential runs down the axon, but doesn’t typically occur anywhere else on the neuron. So just consider the axon here. We’ll consider the remainder of the neuron in the postsynaptic potential section of this unit. You saw what happened when the voltage-gated channels opened in the “gated channels” web page. The Na+ V-gated channel opened first, then it inactivated while the delayed rectifier opened. During the open times of these channels, ions are flowing across the membrane. Ions are charged, so if charges flow across the membrane, the membrane potential across the axon will change. How does it change? 1. When sodium ions flood into the axon, the inside will get more positive (right? sodium ions are positively charged, so when they enter, they bring a postiveness with them). 2. When potassium ions leave the axon… after a delay due to their slow voltage-gated channel, the delayed rectifier… they restore the normal resting potential. These quick changes
