Gastrointestinal disorders include irritable bowel syndrome, constipation, functional disorders, structural disorders and anal disorders, according to the Cleveland Clinic. Irritable bowel syndrome is a condition that causes the colon muscle to contract more often than normal, and constipation is the difficult or infrequent passing of stools.
Functional disorders occur when the bowel works improperly but looks normal, explains the Cleveland Clinic. Causes of functional disorders include lack of dietary fiber, stress, taking antacid medications that contain aluminum or calcium, lack of exercise and pregnancy. Structural disorders cause the bowel to look and work abnormally. Sometimes doctors treat the condition with surgery. The most common types of structural disorders are diverticular disease, cancer and those affecting the anus.
Diverticular disease occurs in half of all people over the age of 60 and 10 percent of those over the age of 40 in Western cultures, notes the Cleveland Clinic. Diverticulosis usually occurs in the sigmoid colon, located in the lower large intestine. The condition results in small outpouchings on the large intestine's muscular wall, and a lack of dietary fiber is often the cause.
Anal disorders include internal and external hemorrhoids, anal fistula and fissures and perinatal abscesses, advises the Cleveland Clinic. An anal fissure is a crack or split in the anal opening. An anal fistula is an abnormal passageway that develops from the anal canal to a hole near the anal opening. An anal fistula may develop after an abscess is drained. When anal glands on the inside are blocked, the bacteria may cause an infection, which can result in a perianal abscess.