“Gullet” is another word for the part of the vertebrate digestive system known as the esophagus, the muscular passage that food and liquids travel along from the mouth to the stomach. The word gullet tends to be most often used in reference to animals rather than humans, though it is still used to describe the human throat or esophagus. "Gullet" comes from the Latin word gula, which means "throat."
The gullet plays an essential role in the digestive system of vertebrate animals, though it is functionally fairly simple. The organ begins at the back of the oral cavity behind the pharynx. From there it forms a long, mostly straight tube that travels down the neck and chest and through the diaphragm before it connects to the stomach. In vertebrates other than fish, the esophagus runs parallel in the throat to the trachea, or windpipe, which leads to the lungs.
The upper and lower ends of the esophagus are usually kept tightly closed by muscles known as sphincters. These sphincters open when a vertebrate swallows, allowing food, liquid and saliva to pass through. A series of controlled striated muscle contractions then systematically move the contents of the gullet down into the stomach. The movement of the muscles is involuntary and usually goes completely unnoticed by the organism, unless the object swallowed is uncomfortably large, hot, cold or has rough edges. After the contents of the esophagus have reached the stomach, the bottom sphincter closes to prevent the stomach contents from returning to the gullet or mouth.
Problems can arise in the esophagus, generally when the bottom esophageal sphincter does not close properly. Stomach acids can seep back into the esophageal tube. This can cause a burning sensation known as reflux or heartburn.
When the stomach acids travel up far enough in the gullet to be tasted, the sensation is referred to as acid indigestion. Both of these experiences are fairly common, but weekly occurrences sometime indicate a more severe problem. Esophageal cancer — also referred to as gullet cancer — can also occur. In cases where the gullet must be removed, most people can still function without it.