Full Esophagus Description
[Continued from above] . . . travel back by the same force to be thrown out through the mouth, which is called vomiting. The esophagus has rings of muscle at the top and at the bottom. These rings close, or contract, after the food passes through and enters the stomach. If the bottom muscle weakens, stomach contents, along with the stomach acid, may return to the esophagus and cause an uncomfortable, burning sensation known as heartburn.