Structure of the colon.

One's concept of the 'structure of the colon' is determined by the method used for examination: the radiologist, endoscopist, surgeon, pathologist, and electron microscopist have strikingly different perspectives. The gross and macroscopical anatomy, histology, and ultrastructure of the normal colorectum are reviewed. The structures primarily involved in secretion and motility, i.e. the mucosa and muscularis propria, are emphasised. Some important differences between human beings and experimental animals are described.