BIO 282 Lecture 23: Wrapping It Up! Action Potentials and Synaptic Transmission Continued
Document Summary
Action potential triggers release of neurotransmitters: step 1: action potential arrives, step 2: depolarization of the membrane causes voltage-gated ca+2 channels to open, step 3: influx of ca+2 causes synaptic vesicles to release neurotransmitter. Step 4: ion channels in the post-synaptic membrane open when neurotransmitter binds; flow of ions causes change in post-synaptic cell membrane potential. These are ligand-gated and just need a signal to open. If the neurotransmitters were left in the space, the receptor would. Step 5: ion channels in the post-synaptic membrane then close as neurotransmitter is broken down or taken back up by pre-synaptic cell continue to signal continuously. Ligand-gated channels causes the action potential to fire, at which point the voltage-gated channels take over. What would happen when different ligand-gated channels open: ligand-gated na+ channel. Why does the graph return back to normal? normal. At some point, the ligand (neurotransmitter) will be broken down or taken back in, so the channel closes.
