Goldman–Hodgkin–Katz Equation

Biophysics · 1943

Equation: V_m = (RT/F)·ln(ΣP·[ion]ₒᵤₜ / ΣP·[ion]ᵢₙ)
Field: Biophysics
Named After: David Goldman · Alan Hodgkin · Bernard Katz
Year: 1943

Symbols

V_m the membrane's resting voltage · P each ion's permeability (weighting its vote) · the sums run over K⁺, Na⁺, Cl⁻ · reduces to Nernst when one ion dominates

Significance

Real membranes listen to several ions at once, each weighted by how easily it passes — the ~−70 mV hum of a resting neuron. Flip the sodium permeability and the voltage spikes: that reversal, propagating down the axon, is the nerve impulse reading this sentence.