ClipArt ETC
An Image of an esophagus showing how a mass of food, or bolus, passes through the esophagus into the stomach. The tissue in front is relaxed, while the tissue behind the bolus is in contraction. When food is not going through it, the esophagus looks like the wave of contraction in the picture.

Human Esophagus

An Image of an esophagus showing how a mass of food, or bolus, passes through the esophagus into the…