The Morphology of the Gastrointestinal Tract

Abstract

Total internal reflection of light within a glass fibre can be produced by coating with glass of a different refractive index. A bundle of these fibres may be used to illuminate the internal anatomy of the gastrointestinal tract and by means of a collimated bundle an image of the illuminated object can be produced. This is the principle of modern fibreoptic endoscopes. The addition of suction, insufflation and distal tip control enables a complete visual record to be obtained from almost all levels of the gastrointestinal tract and this may be supplemented by biopsy or cytological specimens taken through the endoscope. At the same time, it is possible to collect mucus, bile or pancreatic juice using suitable flexible tubing. The fibreoptic endoscope is undoubtedly the best diagnostic aid for delineating gastrointestinal pathology and in particular those conditions associated with abnormal mucus production.