Dr. Jack Wood, a physiologist at The Ohio State University, has dubbed the enteric nervous system the “little brain in the gut.” Given its roots, it is an apt description. The enteric nervous system is derived from the same part of a growing embryo as the brain. It has more neurons than the brain and has all of the brain’s neurotransmitters, including serotonin. Serotonin is one of the neurotransmitter keys often implicated in depression. Remarkably, ninety-five percent of the serotonin in your body is located in the gut. Only five percent is found in the brain. The common embryologic origin of both the mind/brain and the gut brain is a clue to why the digestive system is the source of symptoms like abdominal pain, bloating, diarrhea, and constipation. Furthermore, the term “gut feeling” reflects accurately the fact that the little brain in the gut has something to do with intuition, instinct, and decision-making.
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