PSY396H1 Study Guide - Midterm Guide: Second Messenger System, Voltmeter, Resting Potential
Document Summary
Ions cannot pass through neuronal membrane without channels. 3 ways to open a channel: ligand-gated ligand binds receptor (extracellular or intracellular) voltage-gated change in membrane potential activated by secondary messenger phosphorylation: mechanically gated. Measure voltage of the extracellular environment, compare voltage of the intracellular environment. 0 mv = same membrane potential (q. does a voltmeter tell you which electrode is immersed in a more negatively charged env. ?) Resting membrane potential vm depends on: na/k pump. Electrostatic gradient (charge on either side of the membrane) Stimulating electrode & recording electrode inserted at different points, record local potentials. Bind to receptors and open +ve ion channels. Bind to receptors and open ve ion channels. Axon hillock (or axon initial segment) excitatory potential from dendrites/soma must depolarize enough here (summation) to trigger ap. Ipsps and epsps can both reach the axon hillock. Absolute refractory period: na voltage channels inactivated (cannot be opened, cannot have another ap)
