What is regurgitation and how does it differ from heartburn?

• A. Regurgitation is the involuntary vomiting; heartburn is a sour taste in the mouth.
• B. Regurgitation involves regurgitation of gastric contents with effort; heartburn is acid reflux burning.
• C. Regurgitation is pain with swallowing; heartburn is chest pain unrelated to meals.
• D. Regurgitation is the effortless return of undigested or partially digested food from the esophagus into the mouth; heartburn is a retrosternal burning sensation from acid reflux.

Answer: (D)

Regurgitation is the effortless return of swallowed material from the esophagus into the mouth, without the need for forceful retching or nausea. It reflects backwards movement of contents and can involve undigested or partially digested food. Heartburn, on the other hand, is a burning sensation felt behind the sternum (retrosternal) caused by acid reflux irritating the esophagus.

So the best statement separates these two ideas: regurgitation as a passive upward flow of swallowed material, and heartburn as a symptomatic burning from acid reflux. The other options mix up regurgitation with vomiting, describe regurgitation as painful or involve incorrect sensations, or reduce heartburn to a sour taste, which doesn’t capture the defining features.