Question

In humans, the pyloric sphincter is located between .

• A. esophagus and stomach
• B. stomach and duodenum
• C. mouth and esophagus
• D. ileum and large intestine

Hint:

"Pyloric" refers to the narrow exit of the stomach, think about what comes right after the stomach.

Answer 1

The Correct Option is B

This question tests basic knowledge of the parts of the gastrointestinal tract and the sphincters that separate them. A sphincter is a ring of muscle that opens and closes to control movement of contents from one part of the tract to the next, and each major junction in the gut has its own named sphincter.

1. esophagus and stomach: The valve at this junction is the lower esophageal sphincter (the cardiac sphincter), not the pyloric sphincter.
2. stomach and duodenum: This is correct. The pyloric sphincter sits at the pylorus, the narrow outlet of the stomach, and controls how much partly digested food (chyme) passes into the duodenum, the first part of the small intestine.
3. mouth and esophagus: The junction here is guarded by the upper esophageal sphincter, formed mainly by the cricopharyngeus muscle, not the pyloric sphincter.
4. ileum and large intestine: This junction has the ileocecal valve, a different structure that stops backflow from the cecum into the small intestine.

The pyloric sphincter is a smooth muscle ring specific to the stomach-duodenum junction, so option (B) is correct.

Let's summarize:

• Each gut junction has its own named sphincter or valve, and they are not interchangeable.
• The pyloric sphincter regulates gastric emptying into the duodenum.

The correct answer is stomach and duodenum.