What Is the Role of Ions in Human Electric Conduction During a Shock?

[brendan_foo]

Hi folks,

I was just looking into conduction as part of an electric shock, as in, the flow mechanism, when I ran across an article about such things, which states:

"However, NO ELECTRONS FLOWED THROUGH YOUR BODY AT ALL. The electric charges in a human body are entirely composed of positive and negative charged atoms. During your electrocution, it was these atoms which flowed along as an electric current. The electric current was a flow of positive sodium and potassium atoms, negative chlorine, and numerous other more complex positive and negative molecules."

This is taken in context about an electric shock.

Ok - for an electrostatic case, understandably surface electrons will naturally build up a net high potential and lead to a tiny low current shock etc.. etc.. But in regards to a shock due to electric current, in a conventional sense, surely the body acts as a conduit for electrons to flow.

The argument that the flow is of cat/anions present in the body seems plausable, but however, the body consists of a somewhat finite concentration of such charge carriers. To insist that "NO ELECTRONS FLOW" PERIOD, would suggest that the human body acts as a dielectric upon the point where the ions in the body converge to their respective opposite polarities. Thusly maintaining a potential difference across the body, but no current would surely flow after the transient current in the body subsides.

Also, isn't it ludicrous to think that such potassium, sodium etc.. ions would flow to a conductor and contribute a proportion of the algebraic sum of current.

This one threw me off a little.. Any insight would be greatly appreciated.

Many thanks
Brendan

 

[Claude Bile]

You have to consider charge mobility in this case. Sure, there are electrons in our body, but are these electrons mobile? They aren't because metallic lattices do not occur naturally within the human body. Consequently they aren't going to carry any current.

Ions on the other hand ARE mobile, given the fact that we are 90% water and our blood in particular is a fairly good conduit for these ions to flow.

Since the ions are far more mobile, they will act as the charge carriers.

Now, in your scenario, once the ions have reached their opposite poles - they are no longer mobile and current flow would then fall to electrons. This does not happen until a good portion of the ions become immobilised however. This leads me to believe that when the articles says that no electrons flowed through your body at all, it is probably assuming that ions remain mobile enough throughout the electrocution to carry all the current, which is not an unreasonable assumption.

Claude.

 

[brendan_foo]

Definitely a possible scenario that I considered, the case where the electrocution process occurs during a time frame where the body borne ions are still in a configuration where they could be charge carriers. So the assumption is on a long duration of transient current, by which time the subject in question would be long dead before any steady state is ever achieved. Makes sense; I just thought it was kind of dangerous to make such a bold statement without elaborating the mechanism in its entirety. I suppose I should've taken it into context. I had to clarify anyway.

Thankyou for your help!

 

[Gokul43201]

If the article is talking about electrocution from an AC current (as would be expected), the steady state condition that Claude described would never occur. The current flowing through the body would then be almost entirely ionic. By saying "no electrons" are flowing, the article means to say that the ionic current vastly and overwhelmingly exceeds the electronic current.

Notice that I have to resort to highly subjective adjectives to support the statement made by that article.

 

[brendan_foo]

Yes, certainly so!

Again, I should have stipulated my argument of the DC case. I just conjoured up a mental projection of a person of great stature and abnormal tolerance to shock and a mineral deficiency getting in the path of a DC line and eventually having some balloons sticking to him due to his polarization.

Cheers guys