PSL300H1 Study Guide - Final Guide: Ion, Membrane Potential, Exocytosis
7 Jan 2017
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Membrane potential: resting membrane potential (rmp, equilibrium potential, na+ channels (i. e. , voltage-gated na+ channels) Action potential: refractory periods, absolute refractory periods, relative refractory periods, na+/k+ conductance, after-hyperpolarization. We know that the na+/k+ pump creates the concentration gradient, and the membrane is permeable to k+ at rest. Membrane is most permeable to k+ at rest, but na+ and cl- ions are also diffusing somewhat. So we have another equation that puts all of the ion species into consideration. Includes k+, na+, and cl- with their relatively permeability: recall: k+ is the major player at rest, having the greatest permeability, whereas na+ and cl- have low permeability. Actual membrane potential can be calculated from an expanded equation containing a term for each diffusible ion species. From the goldman equation, em can be calculated it is about - Nernst equation tells us ek+ = -90mv.
