This is a quite dilemma and not only your Instructor faces it. No one can ever find a convincing answer without tracing the origins of these terms. Note that the charge current is a construct of physics and when applied on biological system, by giving electrical stimulation (i.e. electrons) would generate charge current. This charge current would change the depolarization state of the membrane and trigger ionic current, which at threshold value, causes action potential. How such charge current occurs in biology has never been seriously considered although it is conceived that mechanical (e.g. touch), thermal (hot/cold), olfactory, gustatory, etc stimuli can cause conformational changes on their receptors to cause charge current transmitted as ionic current across the axon fibers. I hope I am correct
