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Lesson 9: Communication via NeuronsOrganization of the Nervous SystemNerve Impulse TransmissionElectrical potentialoInside more negative than outsideStimulation causes electrical changesMembrane transport proteinsoIon channelsLeakageGatedOnly open in response to stimulus
oSodium potassium pumpHelps establish and maintainconcentration gradient forpotassium and sodium The Sodium Potassium PumpEstablishment of the Resting Membrane Potential
Channels make it leakyInside the cell are a number of negatively charged proteins and amino acidsResult in the build up of charged differences across the cell membrane known as resting potentialCharge differences are analogous to a polaroid batteryAverage resting potential = -70 mvDisruptions to the resting potentialGraded potentials: small continuous changes to the membrane potentialoDepolarization (less negative)oHyperpolarization (more negative)Gated Channels (normally closed but open in response to a stimulus)oChemically gated channels Acetylcholine binds to the receptor Binding causes the channel to open allowing sodium to diffuse into the cellSince sodium is a cation this causes the membrane to be less negative (or depolarized)oVoltage gated channels