Digestive System

This chapter provides an overview of species differences in the anatomy and physiology of the gastrointestinal system among rodents, dogs and primates, emphasizing that the dog is a good model for functional aspects of the human gastrointestinal tract. It describes and discusses the human relevance of drug-induced changes in the mouth, oropharynx, teeth and salivary glands of laboratory animals. It describes the pathology that can be seen in the esophagus. It discusses changes that can be seen in the rodent forestomach and their usual but incomplete lack of relevance for humans. Spontaneous and drug-induced inflammatory and proliferative disorders found in the stomach, small and large intestines are described in detail particularly those that result from treatment with non-steroidal anti-inflammatory drugs and anticancer therapies. It also discusses the relevance of gastrointestinal neoplasms that may be found in rodents following treatment with therapeutic agents. Keywords mouth, oropharynx, salivary glands, esophagus, forestomach, glandular stomach, small intestine, large intestine, drug safety, comparative pathology, neoplasia