Final answer:
The myenteric and submucosal plexuses form the enteric nervous system, which regulate motility and digestive secretions in the alimentary canal. They contain enteric neurons that are targeted by autonomic preganglionic fibers, which then influence digestive functions.
Step-by-step explanation:
The myenteric plexus, also known as the plexus of Auerbach, and the submucosal plexus, or plexus of Meissner, comprise the enteric nervous system, which provides intrinsic innervation to the alimentary canal. The myenteric plexus is situated in the muscularis layer and is primarily responsible for the regulation of gut motility, including the rhythms and force of contractions. Meanwhile, the submucosal plexus is found in the submucosal layer and plays a key role in regulating digestive secretions and responding to the presence of food.
These plexuses contain enteric neurons, which receive input from long autonomic nervous system (ANS) fibers that synapse within these enteric plexuses. The enteric plexuses then innervate smooth muscle and glandular tissues, directly affecting digestive functions such as motility and secretion.