A sphincter is at the end of the esophagus connecting to the stomach which keeps the food from coming back out and lets more food in
The esophagus begins at the pharynx and at the stomach.
Food enters the esophagus when it is swallowed.
nothing i don't think i belive it is just your stomach,because the esophagus is a long tube that goes down to your stomach so yep i think that's the answer