Answer:
The lower esophageal sphincter, or
cardioesophageal sphincter, or
gastroesophageal sphincter
Step-by-step explanation:
As the name suggests, the lower esophageal sphincter or the gastroesophageal sphincter, is located between the esophagus (esophageal) and the stomach (gastro-). It is a group of smooth muscles (ring-like in structure) that prevents the backflow of food and gastric juices from going back up the esophagus. If this is impaired or weakened, then you may develop GERD or gastroesophageal reflux disorder, or heartburn.