PHYSL212 Lecture Notes - Lecture 3: Resting Potential, Active Transport, Phosphorylation
16 Sep 2016
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Physl 212 - lecture #3 - electrical signaling: membrane potentials. Describing changes in membrane potential: by convention. Vrest = resting potential = special value of vm. Inward current: cations flowing into cell, anions out of cell. Negative: outward current: cations flowing out of cell, anions into cell. Positive: n before p, i before o. Cells have a negative resting potential: at rest: inside is negative. Due to difference in ion concentration and permeability across the membrane. K+ is permeable to the cell at rest. Concentration gradient maintained by active transport of k + and na: # of ions are negligible, don"t need a lot of ions to pass through membranes to produce an electrical signal. Open/close: all electrical signalling results from fluxes of ions through channels. Change vm (passively: multi-subunit proteins, can be activated or inactivated. Binding of calcium: voltage gate inactivation. Facilitates inactivation gates: na+/k+ channels very important.
