Gastric Distension

Gastric distension is the expansion of the stomach as its volume increases, most commonly when food or liquid enters during a meal. As the stomach fills, its wall stretches and wall tension changes. These mechanical changes provide information about gastric filling and contribute to gastrointestinal signals involved in sensations such as fullness and the termination of eating .^1,2

Mechanical information from gastric filling is detected by mechanosensitive sensory endings in the stomach wall. These endings respond to features such as stretch and wall tension and transmit signals toward the central nervous system, including through vagal sensory nerves. In humans, experimentally increasing gastric volume can increase sensations of fullness, while greater distension can eventually produce discomfort, nausea, or pain .^1,2

Gastric distension does not depend simply on the volume swallowed. During eating, the upper stomach undergoes gastric accommodation, a reflex relaxation that allows it to receive a meal while limiting the rise in intragastric pressure. The degree of distension and resulting mechanosensory signaling therefore depend on the interaction between stomach volume, wall tension, muscular relaxation, and gastric emptying .¹

Gastric distension is not synonymous with satiety or satiation. It is one mechanical signal that contributes to the regulation of food intake. As nutrients leave the stomach and enter the small intestine, additional nutrient-sensitive neural and hormonal signals also contribute to meal-related feedback. Gastric distension is therefore one component of the broader gastrointestinal response to a meal .^1,2