In a voltage-clamp experiment on a squid giant axon, the membrane potential is clamped at +20 mV, as shown below. Within the same time frame, which of the curves A to D better show qualitatively how the total membrane current changes? A positive value of the current represents an outward flow of cations.

Question

In a voltage-clamp experiment on a squid giant axon, the membrane potential is clamped at +20 mV, as shown below. Within the same time frame, which of the curves A to D better show qualitatively how the total membrane current changes? A positive value of the current represents an outward flow of cations. In a voltage-clamp experiment on a squid giant axon, the membrane potential is clamped at +20 mV, as shown below. Within the same time frame, which of the curves A to D better show qualitatively how the total membrane current changes? A positive value of the current represents an outward flow of cations.

Quizplus · Accepted Answer

The rapid opening of the sodium channels leads to sodium influx, i.e. a negative current. The slow opening of the potassium channels leads to potassium efflux, i.e. a positive current. The latter current persists as long as the voltage-gated K? channels stay open.

In a Voltage-Clamp Experiment on a Squid Giant Axon, the Membrane