Which factors can increase gastric emptying rate?

• A. Liquids and gastric distention; anticholinesterases and cholinergics
• B. Solids and fats
• C. Guanethidine
• D. Narcotics

Answer: (D)

Gastric emptying rate is driven by the form of the ingested material and by autonomic control of the stomach's smooth muscle. Liquids tend to empty faster than solids because they don’t require the same mechanical grinding and mixing; the stomach can transfer liquid chyme into the duodenum more readily. Gastric distention stimulates stretch receptors that activate vagovagal reflexes, increasing antral contractions and promoting emptying into the small intestine.

Cholinergic signaling accelerates gastric motility. Increasing acetylcholine levels (with acetylcholinesterase inhibitors) or directly stimulating muscarinic receptors (cholinergic agonists) enhances smooth muscle contraction in the stomach, speeding emptying. In contrast, narcotics slow gastric emptying by dampening GI motility, so they do not increase the rate. Fats slow emptying because they trigger feedback signals like cholecystokinin that slow gastric processing to optimize digestion.