Ulcerative colitis primarily involves which part of the gastrointestinal tract?

• A. Small intestine
• B. Stomach
• C. Liver
• D. Large intestine

Answer: (D)

Ulcerative colitis is defined by inflammation that stays in the large intestine, specifically the colon and rectum, with a continuous pattern starting at the rectum. This location explains the classic symptoms of UC, such as frequent diarrhea with blood and abdominal cramps, because the disease affects the mucosal lining of the colon. The inflammation is limited to the colon and does not typically involve the small intestine or other organs as the primary site, which is why the large intestine is the correct choice. In contrast, Crohn’s disease can affect the small intestine and other parts of the GI tract and often has skip lesions, helping to distinguish it from UC.