1 The upper and lower esophageal sphincters act as valves that open to let food pass and close to prevent stomach acid or food from flowing back into the esophagus, helping prevent reflux.

2 Peristalsis in the esophagus is a strong, coordinated wave that pushes food down quickly, while in the intestines, peristalsis is slower and more rhythmic to mix and move food along for digestion and absorption.

3 Esophageal motility is controlled by the vagus nerve and the enteric nervous system, which coordinate muscle contractions through signals responding to swallowing and sensory input.

4 GERD is caused by a weak or relaxed lower esophageal sphincter allowing stomach acid to flow back into the esophagus, leading to irritation and inflammation.

5 Barrett’s esophagus develops when chronic acid reflux damages the esophageal lining, causing cells to change type—a condition that increases the risk of esophageal cancer.

6 Common symptoms of esophageal cancer include difficulty swallowing, chest pain, and weight loss. Early diagnosis is hard because symptoms often appear only in advanced stages.

7 Esophageal strictures form when repeated damage causes scar tissue to narrow the esophagus. Treatments include dilation procedures and medications to reduce acid reflux.

8 Achalasia is a disorder where the lower esophageal sphincter fails to relax properly and esophageal muscles don’t contract normally, causing difficulty swallowing and food buildup