What is narcosis and why does it happen?

[bfw]

I am new to the diving thing and I am hearing all these new words. Just trying to learn as much as I can form everyone on here. So with that said what is narcosis and how does it happen?

I notice you're not asking about the intricate physiology, or the chemical reasons for the anesthetic effect of nitrogen, but rather "what is narcosis?" Your instructor and/or textbook are where you should turn first for these answers. If you have completed your certification without learning this, then you need to go to your instructor and demand your money back.

 

[bfw]

Is there not one shred of evidence of long term nitrogen exposures at high partial pressures being associated with some sort of neurological changes?

Nitrous oxide is a powerful oxidizer, so I can understand it being associated with organ (liver) toxicity.

You're probably thinking of its effect on automotive engines. In that case it's an oxidizer because it rapidly decomposes into nitrogen and oxygen, so it creates high concentrations of oxygen. Certainly, breathing it long enough might lead to chronic oxygen toxicity, but that's probably the extent of it.

 

[bfw]

The effects of nitrogen on divers and nitrous oxide on land-dwellers are probably somewhat similar, and may be produced by similar mechanisms. The interesting thing is that the actual chemical events that lead to narcosis (or general anesthesia) are not understood, despite many years of research.

It is the same mechanism, and they know the nitrogen occupies spaces essential to neural activity, but not much more than that.