Pathological Processes in the Colon

Ulcerative or inflammatory lesions may affect the physiology of the small and large intestine. Ulcer formation entails a circumscribed loss of tissue from the surface of an organ, which results from necrosis following cell destruction by chemicals and the like, or by restriction of the blood supply. Ulcers are among the most common and important lesions. Those that do not penetrate the muscularis mucosa are called erosions. Ulcerative conditions in humans must be differentiated from malignant ulcers, which are associated with neoplasia. Among 

6 A Practical Approach in the Design of Colon-specific Drug Delivery Systems 

Crohn s disease is granulomatous and in most cases it is a simultaneous disease of the ileum and colon. The primarily inflamed region is the distal ileum, and all intestinal layers are thickened. The mucosal surface is reddened, nodular, and cobblestone-Uke, with mnltiple linear ulcerations. The mucosal layer is thickened by inflammatory infiltrate, the submucosa and serosa by fibrosis, and the serosa by hypertrophy. Chronic nlcerative colitis is a systemic disease that starts at the rectum or the sigmoid colon and progresses proximally to involve the entire left side of the colon. The colonic crypts are the first sites of cell damage and death, and the disease primarily involves the mucosal layer of the intestine. 

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