What is the primary factor that leads to nitrogen narcosis in divers?

Nitrogen narcosis primarily occurs due to the increased partial pressure of nitrogen at greater depths. As divers descend, the pressure around them increases, and it affects the gases they breathe. Nitrogen, which makes up a significant portion of air, enters the lipid membranes of the brain cells. The increased levels of nitrogen alter the cellular function and can lead to effects similar to alcohol intoxication, such as impaired judgment and coordination.

This mechanism highlights the importance of understanding how gases behave under pressure and how they interact with biological structures within the body, particularly at depth. The ability of nitrogen to dissolve into the fatty tissue and membranes in the brain is crucial, as it fundamentally alters normal neurological function, leading to the symptoms associated with narcosis. This understanding underscores the risks involved with diving at deeper levels without proper training and precautions.