What part of the gastrointestinal tract does ulcerative colitis affect?

Ulcerative colitis primarily affects the colon, which is the large intestine, and the rectum. It causes inflammation and ulceration of the inner lining of these areas. Unlike Crohn's disease, which can affect any part of the gastrointestinal tract, ulcerative colitis is limited to the colon and rectum. The condition can lead to various symptoms, including abdominal pain, diarrhea, and rectal bleeding.