What is electricity

[Michael]

I was wondering what exactly is happening when we say "electrical current"?

Also, how do electrical currents interact with nerves? I understand that it's true to say the Na/K gradient changes the potential but what does this mean?

I mean, why is it that moving electrical charges from one side of the membrane to the other should make a damn bit of difference? Is water important? Should we view nerves like mitochondria or like batteries?

I suppose I was thinking about the real fundamental properties of things and hence the post.

So? Anyone?
Michael

[Vkothii]

The nervous current is due to ions drifting across a membrane with a gradient, and adiabatic pumping against a gradient.
In a metal conductor current is due to electron drift, which is linear for a DC current, and you can use an AC current to pump electrons into a DC channel.
The mammalian heart is an AC pump (essentially a sphere that contracts), that produces a direct current of fluid (in vascular channels). It's all about pumps, you see.

[Michael]

got a good animation? I think when I see it, it's easy to grasp...

also, I did calculus based physics and I seem to remember being told to think of current like a real current but.. well I forgot all of it :bawl:

Is it possible to think of neurons like a current? Or is that not correct?

[Vkothii]

Yes, an ion current. The action potential travels like a wave along axons, the membrane depolarises spontaneously.
Not like ions travel in a liquid between electrodes, more like the way they would diffuse across a membrane or through a gel; without the sheathing the charge would dissipate into an aqueous intracellular phase. That's a few more big words.

[cosmictraveler]

Electric current is the flow (movement) of electric charge. The SI unit of electric current is the ampere, and electric current is measured using an ammeter. For the definition of the ampere, see the Ampere article.

The electric charge may be either electrons or ions. The nature of the electric current is basically the same for either type.[

The mobile charged particles within a conductor move constantly in random directions, like the particles of a gas. In order for there to be a net flow of charge, the particles must also move together with an average drift rate. Electrons are the charge carriers in metals and they follow an erratic path, bouncing from atom to atom, but generally drifting in the direction of the electric field.

A flow of positive charge gives the same electric current as an opposite flow of negative charge. Thus, opposite flows of opposite charges contribute to a single electric current. For this reason, the polarity of the flowing charges can usually be ignored during measurements. All the flowing charges are assumed to have positive polarity, and this flow is called Conventional current.

In solid metals such as wires, the positive charge carriers are immobile, and only the negatively charged electrons flow. Because the electron carries negative charge, the electron motion in a metal is in the direction opposite to that of conventional (or electric) current.

http://en.wikipedia.org/wiki/Electric_current