Auerbach's myenteric plexus controls motility; Meissner's submucosal plexus controls secretion
Expansion
- Myenteric (Auerbach’s) plexus - between the circular and longitudinal muscle layers. Controls motility and peristalsis
- Submucosal (Meissner’s) plexus - in the submucosa. Controls secretion and local blood flow
Together they form the enteric nervous system, containing more neurones than the spinal cord and capable of operating independently of central input, the “second brain”. Parasympathetic (vagal and pelvic) input is generally excitatory and sympathetic input inhibitory, but both modulate rather than command.
Failure of neural crest cells to migrate the full length of the gut leaves both plexuses absent distally, Hirschsprung disease. The aganglionic segment cannot relax, so it is narrow, with dilatation of the normal bowel proximally. Diagnosis is by rectal suction biopsy showing absent ganglion cells, and the disease always involves the rectum and extends proximally without skipping.