I find regrettable that the reasoning is still explained/oversimplified in terms of "electric potential tells body to do this". This is utterly nonsensical determinism, unhelpful when trying to understand hugely complex and dynamic systems. To say that ions interact with their environment and affect it, through their electrical properties (and maybe chemical too), would be much closer to the reality being described here.

To make an analogy of why determinism is not helpful in biology, consider a white blood cell catching a few bacteria that would otherwise have tried to attack the lungs. Determinism would have us say this white blood cell is protecting the lungs, as if it were its goal. But a white blood cell is just that, a single cell, with no idea that things such as lungs exist or that they need protecting. A white blood cell is just a hunter that recognized something it could eat, and ate it.

If interested in the topic, I was paraphrasing "neither god nor gene" there, a book by Kupiec and Sonigo, and the one read that changed the way I understood biology when I was an undergrad in the field.