[Tube that connects the pharynx to the stomach. In mammals, the oesophagus connects the buccal cavity with the stomach. The stratified squamous non-keratinised epithelium lining the buccal cavity is continued through the pharynx down into the oesophagus. The lowest part of the oesophagus (ca. 2 cm) is lined with gastric mucosa and covered by peritoneum. The main body of the oesophagus is lined with small, simple mucous glands. Each gland opens into the lumen by a long duct which pierces the muscularis mucosae (Wilson and Washington, 1989). A sphincter is situated at the point where the oesophagus enters the stomach to prevent gastro-oesophageal reflux, i.e. to prevent acidic gastric contents from reaching stratified epithelia of the oesophagus, where they can cause inflammation and irritation (Wilson and Washington, 1989; Brown et al., 1993).]
[An organic molecule or ion (usually a metal ion) that is required by an enzyme for its activity. It may be attached either loosely (coenzyme) or tightly (prosthetic group).]
[A protein with core architecture consisting of a signal sequence, a Class II histocompatibility antigen, alpha domain (Pfam:PF00993) and an Immunoglobulin C1-set domain (Pfam:PF07654); these form the extracellular domain and are followed by a single-pass transmembrane region and a small cytoplasmic region.]
