<P> The enteric nervous system in humans consists of some 500 million neurons ( including the various types of Dogiel cells ) , one two - hundredth of the number of neurons in the brain , five times as many as the one hundred million neurons in the human spinal cord , and about 2 / 3 as many as in the whole nervous system of a cat . The enteric nervous system is embedded in the lining of the gastrointestinal system , beginning in the esophagus and extending down to the anus . </P>
the enteric nervous system is part of the peripheral nervous system and is found in the
lining of the gastrointestinal system , beginning in the esophagus and extending down to the anus