Fundamentals of Neurogastroenterology: Physiology/Motility – Sensation

The fundamental gastrointestinal functions include motility, sensation, absorption, secretion, digestion, and intestinal barrier function. Digestion of food and absorption of nutrients normally occurs without conscious perception. Symptoms of functional gastrointestinal disorders often are triggered by meal intake, suggesting abnormalities in the physiological processes are involved in the generation of symptoms. In this article, normal physiology and pathophysiology of gastrointestinal function, and the processes underlying symptom generation, are critically reviewed. The functions of each anatomic region of the digestive tract are summarized. The pathophysiology of perception, motility, mucosal barrier, and secretion in functional gastrointestinal disorders as well as effects of food, meal intake, and microbiota on gastrointestinal motility and sensation are discussed. Genetic mechanisms associated with visceral pain and motor functions in health and functional gastrointestinal disorders are reviewed. Understanding the basis for digestive tract functions is essential to understand dysfunctions in functional gastrointestinal disorders.