Enlargement of the liver and spleen causes the abdomen to distend. A bellows is used to insufflate air to distend the rectum. Unlike the epithelial lining of most organs, transitional epithelium can flatten and distend. This is usually not noticeable until enough fluid has collected to distend the abdomen. Saline irrigation to distend the vagina is often used to maximize visualization. When full, his abdomen would distend "like a huge balloon". In the breeding season, the male is able to distend its striking red gular sac. Water enema may be administered as well in order to distend bowel loop (MR-colonography).