When it comes to major nerves in the human body, most people have heard of the optic and olfactory nerves, the facial and trigeminal nerves, and certainly—if they have been in pain—the sciatic nerve. Yet one of the body’s most consequential nerves that affects everything from mood, the immune system, heart rate and digestion to depression, post-traumatic stress disorder, and inflammatory bowel disease has somehow not become a household word: the vagus nerve.
The vagus nerves—there are actually two of them on each side of the body—are the longest nerves in the human body, originating in the brain and ending at the abdomen. The vagus nerve, part of the parasympathetic nervous system, unites the autonomic nervous system and sympathetic nervous system, which creates homeostasis or balance in the body.
