NROB60H3 Lecture Notes - Lecture 6: Resting Potential, Alpha Helix, Batrachotoxin
Document Summary
Firing frequency of action potentials reflects magnitude of the depolarizing current and is one way stimulation intensity is encoded in the nervous system. Firing frequency reflect the magnitude of the depolarizing current. Action potential in theory: initially assume all channels are closed, open k channels and k flows out of cell, at equilibrium, no net k current, at rest. Stipulate the na membrane channels to open. Sodium membrane (sodium ions that are actually changing: repolarizing ( falling ) Efflux of k+ takes vm back towards ek: we have flipped the membrane potential by changing the relative ionic permeability of the membrane, rising phase has inward na+ current and falling phase has outward k+ current. At rest, neural membrane thought of as a k+ membrane because it is permeable only to k+ and potential is about that of the potassium equilibrium potential. Active membrane is a na+ membrane permeable mainly to na+ and this potential tends towards the na+ equilibrium potential.
