What is the function of the pyloric sphincter?

• A. Absorbs nutrients
• B. Produces enzymes
• C. Regulates emptying of stomach contents into the duodenum and prevents backflow
• D. Controls entry of chyme into the esophagus

Answer: (C)

The pyloric sphincter acts as a valve between the stomach and the duodenum, regulating how much chyme leaves the stomach and enters the small intestine. It opens briefly to release small amounts of stomach contents in a controlled, rhythmic way, letting digestion proceed at a manageable pace. It also stays closed to prevent backflow from the duodenum into the stomach, protecting the stomach from reflux and ensuring the duodenum isn’t overwhelmed by highly acidic material. Absorption happens mainly in the small intestine, so that’s not the role of this sphincter, and enzyme production occurs in other organs. The entry of chyme into the esophagus is controlled by a different sphincter, not this one. So the key function is regulating gastric emptying into the duodenum and preventing backflow.