Gastrointestinal Innervation
Start with the big picture
The ENS is a semi-autonomous network in the gastrointestinal wall. Its myenteric plexus is associated with motility, while its submucosal plexus helps regulate secretion and local blood flow. Sensory neurons detect signals such as stretch and chemical changes; interneurons integrate information, and motor neurons act on muscle and secretory cells. Autonomic input further modulates GI activity: parasympathetic pathways generally increase motility and secretion and relax sphincters, whereas sympathetic pathways reduce motility and blood flow and constrict sphincters. Short reflexes are contained within the ENS; long reflexes involve the CNS through autonomic pathways. The gastrocolic reflex is an example of a long reflex.
What you'll learn
- Identify the roles of the myenteric and submucosal plexuses.
- Describe the sensory, interneuron, and motor neuron roles in the ENS.
- Contrast parasympathetic and sympathetic effects on GI activity.
- Distinguish short ENS reflexes from long CNS-involving reflexes.
- Recognize the gastrocolic reflex as an example of a long reflex.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
