ABSTRACT
The alimentary tube is lined with a mucous membrane consisting of a superficial layer of epithelium resting on a layer of connective tissue called the lamina propria. The radiation sensitivity of the various parts of the alimentary tract varies with the type of epithelium in the mucosa and glands, with the degree of vascularization, and possibly with other normal variables. At the point of joining of the esophagus and the stomach at the cardia of the stomach, the stratified squamous epithelium of the esophagus changes sharply to the simple columnar epithelium of the glandular stomach. The small intestine has the most rapid cell turnover of the various parts of the alimentary tract, a few days, and manifests the consequences of cellular effects of radiation earlier. Although acute ulceration may not be caused primarily by vascular damage, damage to the vasculature and connective tissue may influence the course, healing, or tractibility of such ulcers.
