Enteric Nervous System

Overview
  • The GI system contains almost as many neurons as the spinal cord. These neurons are organized in a distributed network that spans the entire length of the alimentary tract from the mouth to the anus. This network of neurons exerts substantial, independent control on GI functions and is termed the "Enteric Nervous System".
Location and Functionality
  • Most of the neurons of the enteric nervous system are located in the submucosa and the muscularis propria of the GI Tract. The submucosal plexus is located within the GI submucosa and mostly regulates GI Secretion. The myenteric plexus is located between the circular and longitudinal muscle layers of the GI muscularis propria and mostly regulates GI motility.
Circuitry
  • Internal Connections:
    • The submucosal and myenteric plexuses possess significant connections between one another. There is also significant neural input from the GI epithelium, especially to the submucosal plexus, which helps regulate secretion and absorption.
  • External Connections
    • The enteric nervous system also possesses significant afferent and efferent connections with the autonomic nervous system. This allows the CNS to modulate the alimentary tract and conversely allows the alimentary tract to modulate central behavior. The connections between the enteric nervous system and the autonomic nervous system are described in Autonomic GI Neural Control.