myentericus

The myentericus, more commonly referred to as the myenteric plexus or Auerbach’s plexus, is a major component of the enteric nervous system. It consists of interconnected neurons and glial cells arranged in a network between the circular and longitudinal layers of the muscularis externa throughout much of the gastrointestinal tract, from the esophagus to the internal anal canal.

Anatomically, the myenteric plexus lies between the two muscular layers of the gut wall. It forms a continuous layer that coordinates motor activity along the length of the intestine. In concert with the submucosal (Meissner’s) plexus, the myenteric plexus helps regulate gut motility, tone, and reflexes that control peristalsis and rhythmic contractions.

Functionally, the myenteric plexus integrates sensory information from the gut and modulates smooth muscle activity. It contains motor neurons that promote contraction and pathways that promote relaxation, with input from the autonomic nervous system. Parasympathetic stimulation generally enhances myenteric activity, promoting propulsion and coordinated motility, while sympathetic input tends to inhibit motility.

Developmentally, the myenteric plexus arises from neural crest cells that migrate into the gut during embryogenesis. Disruptions in this process can lead to congenital motility disorders.

Clinical significance includes Hirschsprung disease, in which there is congenital absence of enteric neurons in the distal bowel, affecting both myenteric and submucosal plexuses. This results in impaired relaxation and severe functional obstruction. Other enteric neuropathies or degenerative changes affecting the myenteric plexus can contribute to intestinal dysmotility and pseudo-obstruction in adults.

The myenteric plexus is one of two principal enteric nervous system networks, the other being the submucosal (Meissner’s) plexus, which primarily regulates secretion and local blood flow.