vertebrate organ through which food passes to the stomach
The oesophagus (or esophagus) is also called the gullet. It is the part of the gastrointestinal system between the mouth and the stomach. It connects the pharynx and the stomach. It is about 25 centimetres (9.8 in) long.
The oesophagus is lined with muscle, and is lubricated. Its muscle pushes food down into the stomach. The oesophagus can contract or expand to allow for the passage of food. The muscular movement that pushes the food down the oesophagus is called peristalsis. At the entrance to the stomach there is a ring of muscle called a sphincter. This is usually closed, but relaxes as food approaches, allowing it to enter the stomach. In the stomach, the food is churned until it turns into a soupy mixture called chyme.