ATI TEAS (Test of Essential Academic Skills) Version 7ScienceMedium
A patient is experiencing chronic heartburn and acid reflux. A diagnostic procedure reveals a weakened muscular ring that allows stomach acid to flow back into the esophagus. Which of the following structures is most likely dysfunctional?
- AInternal anal sphincter
- BPyloric sphincter
- CLower esophageal sphincter
- DIleocecal valve
Show answer & explanationAnswer & explanation
Correct answer: C. Lower esophageal sphincter
The lower esophageal sphincter (LES) is a muscular ring that prevents stomach contents from refluxing into the esophagus. Its weakening directly leads to heartburn and acid reflux.
Why the other options are wrong
- A. The internal anal sphincter controls the release of feces from the rectum.
- B. The pyloric sphincter regulates the flow of chyme from the stomach to the small intestine.
- D. The ileocecal valve controls the passage of material from the small intestine to the large intestine.
Lower Esophageal Sphincter (LES)
A ring of muscle at the junction of the esophagus and stomach that prevents reflux of stomach contents into the esophagus.
- Relaxes to allow food into the stomach.
- Contracts to prevent acid reflux.
- Dysfunction leads to gastroesophageal reflux disease (GERD).
Memory trick: LES: Less Esophageal Sizzle from Stomach.