Expansion
Gastrocolic, enterogastric, gastroileal and intestino-intestinal reflexes
Expansion
| Reflex | Trigger | Effect |
|---|---|---|
| Gastrocolic | Food in the stomach | Increased colonic mass movement, urge to defecate |
| Gastroileal | Food in the stomach | Increased ileal motility, opening the ileocaecal valve |
| Enterogastric | Acid, fat or distension in the duodenum | Slows gastric emptying and secretion |
| Intestino-intestinal | Distension or irritation of one segment | Inhibits motility throughout the gut |
| Rectoanal inhibitory | Rectal distension | Internal anal sphincter relaxation |
| Peristaltic (myenteric) | Local distension | Contraction above, relaxation below |
The gastrocolic reflex explains the postprandial urge to defecate, and its exaggeration contributes to symptoms in irritable bowel syndrome.
The intestino-intestinal reflex is the protective mechanism that becomes maladaptive in paralytic ileus, since injury or inflammation anywhere in the abdomen shuts down motility everywhere.
Most are mediated partly by the enteric nervous system and partly by vagovagal pathways, which is why vagotomy alters several of them at once.