How does smoking harm the duodenum?
D004381:Duodenal Ulcer / Q000209:etiology*; D004386:Duodenum / Q000187:drug effects; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects; D006801:Humans; D012907:Smoking / Q000009:adverse effects*