1. Action Potentials

2. Membrane Potential Electrical charge inside a neuron is different than interstitial space Resting membrane potential (RMP) is -70mV Threshold: Different for every neuron, b/w -60 and -50 mV Depolarization: change towards 0 mV All or nothing Hyperpolarization: -80 to -90 mv Repolarization: Returning to RMP

4. Factors Responsible for Membrane Potential Sodium, chloride, and potassium ion concentrations Proteins Leak Channels Gated Channels Sodium Potassium Pump

6. Propagation of an Action Potential Refractory period: the moment voltage regulated Na+ channels open at threshold until repolarization Only move in forward direction Na+ channels open K+ channels open Na+ channels close K+ channels close Na+/K+ pump activates

7. Propagation of an Action Potential Continuous propagation: the movement of action potentials down an unmyelinated axon ~1 meter per second (2 mph) Saltatory propagation: movement of action potentials down a myelinated axon ~18-140 meters per second (40-300 mph) Node of Ranvier: gaps between myelin on an axon Site of ion channels and pumps

8. Neural Communication Synapse: meeting of a terminal ending with a dendrite or effector organ Neurotransmitters: chemicals sent from a terminal ending across the synapse ACh (cholinergic neruons)

9. Neurotransmitter Release Arrival of action potential Release of neurotransmitter Binding of neurotransmitter, depolarization of postsynaptic cell Removal of neurotransmitter Botulism Tetanus

11. Activity Draw a multipolar neuron On the picture, show how an action potential is sent down the axon Label ion channels, and show ion movement On the picture, show how neurotransmitters are sent from one neuron to the next Under the picture, write a paragraph summary of action potentials.