Oesophagus lining. Light micrograph of sectioned tissue from the oesophagus or gullet lining. This tube, which runs from the mouth to the stomach, is lined with a thick, protective epithelium (pink). Beneath the epithelium lies the lamina propria, a layer of supporting connective tissue which contains numerous mast cells (purple). Granules within the mast cells store the chemicals histamine and serotonin, which cause allergic symptoms when they are released. The cells also release heparin, an anticoagulant. Haematoxylin, erythrosine, saffron and alcian blue stain. Magnification unknown.