(3) (10 pts total) The following data were collected from a voltage clamped squid axon. Assume that currents are fit by the Hodgkin-Huxley equations and that ENa= +60 mV, Ex=-100 mV. Recall I=g(Vm-E). Note that both driving force (Vm-E) and conductance (9) change as a function of Vm, and both contribute to the resulting current. Time constants (tau) for m, h, and n particles are given: Vm(mV) Peak_gNa(nS) Peak_gK(nS) Tm(msec) Th(msec) in(msec) -100 001 005 0.2 3 5 -60 0.5 2 0.3 10 5 -20 9.5 8 0.4 3 2.5 20 10 10 0.2 2 60 10 10 0.15 2 100 10 10 0.1 2 For voltage clamp steps from a holding potential of -100 mV: a) (4 pts) At what potential is sodium current greatest? b) (4 pts) At what potential is potassium current greatest? c) (1 pt) At what time does the potassium current reach its peak following a step to -20 mV (estimate that peak occurs at 5*tau)? d) (1 pt) Based on comparing the time constants, which activates first, sodium or potassium current