The esophagus or oesophagus (see American and British English spelling differences), sometimes known as the gullet, is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. The word esophagus is derived from the Latin oesophagus, which derives from the Greek word oisophagos (οισοφάγος). In humans the esophagus is continuous with the laryngeal part of the pharynx at the level of the C6 vertebra. The esophagus passes through a hole in the thoracic diaphragm called the esophageal hiatus. It is usually 25-30 cm long which connects the mouth to the stomach. It is divided into cervical, thoracic, and abdominal parts.
Functions of the esophagus
Food is passed through the esophagus by using the process of peristalsis
. Specifically, it connects the pharynx
, which is the body cavity that is common to the digestive factory and respiratory system with the stomach, where the second stage of digestion is initiated.
The esophagus is lined with mucous membrane, and is more deeply lined with muscle that acts with peristaltic action to move swallowed food down to the stomach.
The layers of the esophagus are as follows:
The junction between the esophagus and the stomach (the gastroesophageal junction
or GE junction
) is not actually considered a valve, although it is sometimes called the cardiac sphincter, cardia
or cardias, but is actually more of a stricture.