BIOLOGY 2A03 Lecture Notes - Lecture 13: Voltage-Gated Potassium Channel, Resting Potential, Neurotransmitter Receptor
30 Mar 2016
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2 factors determine vm: concentraion gradient of ions. Na+/k+ pump (atpase) contributes indirectly to vm by creaing na+ and k+ concentraion gradients. K+ moves out of cell through open channels, inside of cell gets negaive which creates an inwardly electrical force (negaive cell atracts posiive k+ ions) but chemical force sill outwards so. Vm sill gets (-); when ef = cf (ek) no net movement of ions. More permeable ions have a greater inluence on the resing membrane potenial. The way an ion wants to move across a membrane conductance increases as membrane becomes more permeable to that ion. Ex. typical neuron pk+ 25x greater than pna+ so potassium important in making negaive resing vm. Driving forces electrochemical driving force - combined efect of chemical and electrical forces dictates the tendency for ions to difuse across membranes. Resing membrane potenial - vm across membrane when cell at rest (not sending/receiving signals) neurons - resing vm about 70 mv.
