Why does electrical current passing through the human body hurt?

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Discussion Overview

The discussion revolves around the reasons why electrical current passing through the human body causes pain, exploring the physiological mechanisms involved, particularly the roles of nerves and muscles. The scope includes theoretical explanations and some practical implications related to electrical safety.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the pain from electrical current is primarily due to the stimulation of nerves.
  • Others argue that the effects are more complex, involving muscle contractions and potential damage to tissues, particularly at higher current levels.
  • One participant mentions that the human body does not naturally detect electric current, as evolutionary exposure to such currents was minimal.
  • It is noted that small currents, such as those from electrical sockets, can conduct through the body without causing noticeable harm.
  • Concerns are raised about the dangers of alternating current (AC) electricity, particularly its effect on the heart, which can lead to dangerous conditions like fibrillation.
  • Some participants express skepticism about the ability to die from nerve input alone, suggesting that significant current through the brain or heart is more critical.

Areas of Agreement / Disagreement

Participants generally agree that electrical current affects nerves and muscles, but there is disagreement about the mechanisms and implications of these effects, particularly regarding the potential for harm and the evolutionary context of electrical sensitivity.

Contextual Notes

There are unresolved assumptions about the thresholds of current that cause pain or damage, as well as the specific physiological responses involved. The discussion also reflects varying levels of understanding regarding the safety of low-level electrical exposure.

much noise
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What's the electrical current messing up that's causing pain?
 
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Nerves.
 
Care to elaborate? Can't just be nerves, anyway, because I know that sometimes it fries you. And you can't die from a lot of input coming in your nerves. (Can you!?)
 
Because muscles work by maintaining a potential difference along the muscle which, when discharge, causes your muscles to contract. Therefore, when you get electrocuted the excess current messes up this whole system and your muscles convulse (contractt and extend) wildly. Which can be quite painful.
 
However, to really answer you question our body DOESN'T detect electric current. The reason is simply because we never evolved to (not much evolutionary advantage in the natural world, the only exposure to electric current would be when we got struck by lightning). The convulsion of the muscles only occurs at a certain current level. However, we conduct current across our skin all the time and don't notice. If you were to take an oscilloscope (or a volt/multi-meter) and grab each terminal with different hands you would find that you have a 60Hz (depending on what region you're in) current conduction across you right this second. It's coming from your electrical sockets and conducting through you (this current is small of course). But such small currents are harmless to us and we don't notice them.
 
Along with what maverick said, your muscles are controlled by electrical signals, your heart is a muscle. The big danger from AC electricity is that the 60Hz makes your heart try and beat 60 times per second which exceeds the manufacturers recommended specification by quite a large margin - which generally leads to a failure.
 
much noise said:
Care to elaborate? Can't just be nerves, anyway, because I know that sometimes it fries you. And you can't die from a lot of input coming in your nerves. (Can you!?)

Yes, you can. That's what happens when current goes through the brain. It also kills by interfering with the heart's electrochemical triggers, either stopping it completely or causing it to flutter uselessly (a condition called fibrillation).

But the part that hurts is the nerves being electrostimulated.
 
mgb_phys said:
which exceeds the manufacturers recommended specification by quite a large margin - which generally leads to a failure.

lmfao!
 
If I ever have to have surgery I want some those "warranty void if seal broken" and "no user serviceable parts inside" stickers
 
  • #10
mgb_phys said:
Along with what maverick said, your muscles are controlled by electrical signals, your heart is a muscle. The big danger from AC electricity is that the 60Hz makes your heart try and beat 60 times per second which exceeds the manufacturers recommended specification by quite a large margin - which generally leads to a failure.

Cripes, don't get me started on the warranty program either.
 

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