Oesophagus. Light micrograph of a section through a human oesophagus (gullet). The oesophagus is a hollow tube about 25cm in length with a thick wall of mainly smooth or involuntary muscle that conveys fluids and food to the stomach by peristaltic contractions. The inner surface (mucosa) is protected by a thick layer of stratified squamous epithelium where the superficial cells, subject to wear and tear from the passage of food, are continually replaced from upward growth of deeper epithelial cells. Occasional clusters of mucous-type glands below the epithelium provide lubrication to the epithelial surface. Aggregates of fat cells (adipocytes) deep to the mucosa are seen as empty spaces (white). Magnification: x36, when printed 10 centimetres