Gastric emptying, motility and volume of contents

The stomach empties liquids faster than solids. The rate of transfer of gastric contents to the small intestine is retarded by the activity of receptors sensitive to acid, fat, osmotic pressure and amino acids in the duodenum and the small intestine and stimulated by material that has arrived from the stomach. Gastric emptying is a simple exponential or square-root function of the volume of a test meal - a pattern that holds for meals of variable viscosity. To explain the effect of a large range of substances on emptying, an osmoreceptor has been postulated which, like a red blood cell, shrinks in hypertonic solutions and swells in hypotonic solutions. 

Reproduced from C. G. Wilson and N. Washington, Physiological Pharmaceutics, Ellis Norwood, Chichester, 1989. 

Ten rats per group. Measurements on gastric contents made 20 min after the third hourly dose of 1 cm water or antacid by gastric intubation. 

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