ISCI 2A18 Lecture 5: Neuro Lecture Notes
6 Dec 2016
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Na permeability falls not very much effect on vm (permeability already very low). Both na+ and cl- permeability are 0 vm will be equal to k+ equilibrium potential, which is negative. Log of a number less than 1 is negative (based on equation). K+ contribution dominates in the equation, and there is more k+ inside than outside. Potassium will be able to pass through membrane more easily this will depolarize the potential (outside concentration of k+ greater than inside, reverses ratio in eq"n). Cl- will have small effect on membrane potential. K+ has a permeability of 1, na+ has permeability of 0. 04, and cl- has a permeability of 0. 45. There is a theoretical linear relationship between patch potential and channel current, passes through (0,0). All-or-none signal can"t have half an action potential. Cell fires (creates an action potential) only if vm reaches threshold (typically around -40 or -45 mv)
