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How does the enteric nervous system control movement and secretion in the digestive tract?

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Diagram comparing action potential conduction in myelinated and unmyelinated axons, showing a neuron with labeled cell body, myelin sheath, nodes of Ranvier, and the flow of electrical signals along each type of axon. — nervous system In a myelinated axon, the myelin sheath prevents the local current (small black arrows) from flowing across the membrane. This forces the current to travel down the nerve fibre to the unmyelinated nodes of Ranvier, which have a high concentration of ion channels. Upon stimulation, these ion channels propagate the action potential (large green arrows) to the next node. Thus, the action potential jumps along the fibre as it is regenerated at each node, a process called saltatory conduction. In an unmyelinated axon, the action potential is propagated along the entire membrane, fading as it diffuses back through the membrane to the original depolarized region.

The enteric nervous system (ENS) regulates digestive functions through two primary networks of neurons embedded within the wall of the gastrointestinal tract: the myenteric plexus and the submucosal plexus.12

Control of Movement

The Auerbach (myenteric) plexus is located between the circular and longitudinal muscle layers. It regulates peristalsis—the waves of contraction that move digestive products—as well as stationary mixing and churning. By stimulating muscle cells to contract, this plexus maintains muscle tone and coordinates the opening of sphincters to allow the passage of food.13

Control of Secretion

The Meissner (submucosal) plexus, situated in the submucosal tissue, primarily manages the internal environment of the gut. It controls glandular secretions, regulates local blood flow, and alters water and electrolyte transport.13

These plexuses function through three classes of intrinsic neurons: sensory neurons (which detect mechanical or chemical stimuli), interneurons, and motor neurons, which execute the final commands to target cells like glands and smooth muscle. While the ENS can operate independently, it is also modulated by extrinsic pathways from the sympathetic and parasympathetic nervous systems.1