Which neural structure in the GI tract serves as the primary regulator of peristalsis and GI motility, and where is it located?

• A. Myenteric (Auerbach) plexus located between the circular and longitudinal muscle layers.
• B. Submucosal (Meissner) plexus between mucosa and submucosa.
• C. Celiac plexus within the mesentery.
• D. Dorsal motor nucleus of the vagus.

Answer: (A)

The main driver of peristalsis and GI motility is the myenteric (Auerbach) plexus, a network of neurons embedded in the wall of the GI tract between the circular and longitudinal muscle layers of the muscularis externa. This plexus coordinates the rhythmic contractions and muscle tone that propel content along the gut, making it the primary motor regulator of propulsion.

In contrast, the submucosal (Meissner) plexus sits in the submucosa between the mucosa and circular muscle and mainly governs local secretions, absorption, and blood flow rather than the propulsion itself. The celiac plexus is an extrinsic prevertebral network supplying foregut structures, not the intrinsic motor pattern. The dorsal motor nucleus of the vagus provides autonomic input from the brainstem, influencing motility but not generating the core local peristaltic pattern.