In tanks using a flapper-flush valve, the outlet at the bottom of the tank is covered by a buoyant (plastic or rubber) cover, or flapper, which is held in place against a fitting (the flush valve seat) by water pressure. To flush the toilet, the user pushes a lever, which lifts the flush valve from the valve seat.
Intestines make up the digestive tract. Photo Credit Denis Raev/iStock/Getty Images. Your intestines make up most of your digestive tract. Much of your digestion takes place in your small intestine, while your large intestine absorbs water and excretes waste. Inflammation of the intestines is the primary characteristic of inflammatory bowel diseases, or IBDs, which include Crohn's disease and colitis. Though dietary measures cannot cure IBDs, according to the Crohn's and Colitis Foundation of America, certain foods may support intestinal healing and help alleviate symptoms.
Mucous prevents the stomach and duodenum from being damaged by acid and digestive enzymes. If there is a break in the lining (such as an ulcer), the tissue under the lining can be damaged by the enzymes and corrosive acid. If the ulcer is small, there may be few symptoms. The wound can heal on its own. If the ulcer is deep, it can cause serious pain or bleeding. Rarely, acids in the digestive juices may eat completely through the stomach or duodenum wall.