The Enteric Nervous System (ENS) is a very large group of nerves embedded within our digestive system. Not too much is known about this system, so it doesn’t get much press. But consider this: the ENS contains over 100 million neurons – as many as the spinal cord! And the ENS has all the same neurotransmitters as the brain.
“The specific functions and interactions of these neurotransmitters in the enteric nervous system remain largely unknown…Because of the extensive network of nerves, and the immense size and complexity, it is sometimes referred to as the ‘2nd Brain’…the enteric nervous system is quite capable of controlling digestive functions independent of the central nervous system.” – Frederic Martini, Fundamentals of Anatomy and Physiology.