<prompt> Following statements regarding ulcerative colitis is true-Smoking has a protective effectSmoking does not have a protective effectThere is no relation to smokingSmoking causes relapses  <response>: Ulcerative colitis Inflammation invariably involves the rectum proctitis and spreads and also has some bleeding and proximally in a continuous manner to involve the entire colon in some cases pancolitis. In long-standing pancolitis, the bowel can become shoened and post-inflammatory pseudopolyps develop; these are normal or hyperophied residual mucosa within areas of atrophy . The inflammatory process is limited to the mucosa and spares the deeper layers of the bowel wall . Both acute and chronic inflammatory cells infiltrate the lamina propria and the crypts cryptitis. Crypt abscesses are typical. Goblet cells lose their mucus Ref Davidson edition23rd pg 815 