[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Physiology](https://durgical.com/en/physiology/) › [Gastrointestinal](https://durgical.com/en/physiology/#s-gi) › Gastric motility and emptying [Physiology](https://durgical.com/en/physiology/) · [Gastrointestinal](https://durgical.com/en/physiology/#s-gi) # Gastric motility and emptying - Mechanism - Exam priority: medium The stomach stores food, grinds it and hands it to the duodenum in small portions, at the pace the gut can handle. Updated 2026-11-01 Also called: Gastric emptying, Antral pump **See it in 3D:** [Stomach](https://durgical.com/en/anatomy/stomach/) · [Duodenum](https://durgical.com/en/anatomy/duodenum/) · [Vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/) ## Key points - Receptive relaxation and accommodation (vagus, VIP and nitric oxide): the stomach accepts ≈1–1.5 L with little rise in pressure. - The antrum contracts at ≈3/min (the slow-wave rhythm); retropulsion against the closed pylorus grinds the food. - Particles of ≈1–2 mm pass into the duodenum; larger ones return to the gastric body for more grinding. - Liquids empty fast (exponentially); solids empty linearly after a lag phase. Fat slows emptying the most. - Duodenal brakes: CCK (fat), secretin (acid), GIP, the enterogastric reflex and osmoreceptors. - Between meals, the migrating motor complex (phase III) sweeps undigested material into the duodenum. ## What it is The proximal stomach (fundus and body) acts as a reservoir: it relaxes to receive food without a rise in pressure. The antrum is a pump that mixes and grinds with contractions about 3 times a minute, and the pylorus lets only small particles through. Emptying is controlled mainly by the duodenum: if fat, acid or hyperosmolar fluid arrives, hormones and reflexes brake the stomach. ## How it works, step by step - On swallowing, the vagus relaxes the fundus and body before the bolus arrives (receptive relaxation). - Food settles in layers; acid and pepsin start working at the edges. - Peristaltic waves start in the mid-body and grow stronger toward the antrum. - As the wave arrives, the pylorus closes; contents hit it and bounce back (retropulsion), mixing and grinding. - With each wave, a small portion of fluid chyme passes into the duodenum. - Acid, fat and hyperosmolality in the duodenum release CCK and secretin and trigger the enterogastric reflex: the antrum contracts less and pyloric tone rises. - When the duodenum has neutralized and absorbed, the brake releases and the next portion leaves. ## Regulation - *+* **Gastric distension and the vagus**: Increase the strength of antral contractions - *+* **Motilin (fasting)**: Triggers the migrating motor complex - *−* **CCK and GIP (fat in the duodenum)**: Relax the proximal stomach and raise pyloric tone - *−* **Secretin and the enterogastric reflex (acid)**: Reduce antral contractility - *−* **Sympathetic tone, pain, opioids and hyperglycemia**: Delay emptying ## Clinical notes - Hypertrophic pyloric stenosis: an infant aged 2–8 weeks with projectile non-bilious vomiting, a palpable 'olive' and hypochloremic, hypokalemic metabolic alkalosis. - Diabetic gastroparesis: vagal neuropathy → early satiety, nausea, vomiting of retained food and erratic glucose. - Dumping syndrome after gastric surgery: a sudden load of hyperosmolar fluid in the jejunum pulls in fluid and causes vasomotor symptoms. - Fasting before anaesthesia rests on emptying: clear liquids leave long before fatty meals. ## Memory aid 'The duodenum is the doorman': it lets chyme in only once the last portion has been neutralized and absorbed. ## Test yourself Think of the answer, then tap the question to see it. ## Why does a fatty meal stay longer in the stomach? Fatty acids in the duodenum release CCK and GIP and trigger inhibitory reflexes: the proximal stomach relaxes, the antrum contracts less and pyloric tone rises. ## Which acid–base disturbance is expected in hypertrophic pyloric stenosis, and why? Hypochloremic, hypokalemic metabolic alkalosis: vomiting loses gastric HCl; hypovolemia activates aldosterone, which increases renal K⁺ and H⁺ loss. ## What is retropulsion and what is it for? The backward jet of contents when the antral wave hits the closed pylorus. It mixes and grinds food down to particles of ≈1–2 mm that can pass into the duodenum. ## Why could truncal vagotomy cause early fullness? It removes vagal receptive relaxation of the proximal stomach; intragastric pressure rises with small volumes and the patient feels full early. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/physiology/gastric-motility-and-emptying/) ## See it in 3D The structures of Durgical's 3D anatomy where it happens. - [Stomach](https://durgical.com/en/anatomy/stomach/) - [Duodenum](https://durgical.com/en/anatomy/duodenum/) - [Vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/) ## Related topics - [Gastrointestinal hormones](https://durgical.com/en/physiology/gastrointestinal-hormones/) - [The enteric nervous system, slow waves and GI control](https://durgical.com/en/physiology/the-enteric-nervous-system-slow-waves-and-gi-control/) - [Gastric acid secretion](https://durgical.com/en/physiology/gastric-acid-secretion/) - [Vomiting and its control](https://durgical.com/en/physiology/vomiting-and-its-control/) - [Small bowel and colon motility](https://durgical.com/en/physiology/small-bowel-and-colon-motility/) - [Swallowing and esophageal motility](https://durgical.com/en/physiology/swallowing-and-esophageal-motility/) ## Related conditions - [Infantile hypertrophic pyloric stenosis](https://durgical.com/en/conditions/infantile-hypertrophic-pyloric-stenosis/) - [Peptic ulcer disease](https://durgical.com/en/conditions/peptic-ulcer-disease/) - [Type 1 diabetes mellitus](https://durgical.com/en/conditions/type-1-diabetes-mellitus/) - [Type 2 diabetes mellitus](https://durgical.com/en/conditions/type-2-diabetes-mellitus/) - [Metabolic alkalosis](https://durgical.com/en/conditions/metabolic-alkalosis/) ## In Pharmacology - [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/) [← All of physiology](https://durgical.com/en/physiology/) Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given. Sources: [23.4 The Stomach](https://openstax.org/books/anatomy-and-physiology-2e/pages/23-4-the-stomach) (OpenStax (Rice University), 2022); [Pyloric Stenosis](https://www.ncbi.nlm.nih.gov/books/NBK555931/) (StatPearls (NCBI Bookshelf), 2024); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 64). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/physiology/gastric-motility-and-emptying/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/physiology/gastric-motility-and-emptying/