1. The correct answer is b. Most nutrients are absorbed in the small intestine. The stomach helps prepare food for digestion by the action of its enzymes. The food then passes into the small intestine, where it undergoes further digestion and is absorbed by the microvilli. Water and electrolytes are absorbed by the large intestine.

2. The correct answer is a. The stomach is very acidic as it works to initiate digestion of proteins, fats, and carbohydrates. Bicarbonate neutralizes acid and would work against this process if it was in the stomach.

3. The correct answer is c. This pathogen is responsible for most chronic gastritis, peptic ulcer disease, and ultimately stomach cancers. It infects almost half of the population but is asymptomatic in most individuals and does not manifest itself until about age 60 in those who do develop symptoms.

4. The correct answer is b. This is a complex salt of sucrose sulfate and aluminum hydroxide. In the acid environment of the stomach, it becomes a gel-like substance that binds to both defective and normal mucosa and acts as a physical barrier to acid, pepsin, and bile acids. It also increases prostaglandin and mucus production. It has few side effects and is well tolerated.

5. The correct answer is a. Gastric ulcers are more common in people older than age 55 and most common in people older than age 75; these individuals frequently take large amounts of NSAIDs to control arthritis pain, making it the primary cause of ulcers. H. pylori are associated with peptic ulcer disease and in 90% of cases affect the duodenum. An imbalance of protective and aggressive factors, not excess stomach acid, is associated with the development of gastric ulcers. Spicy foods do not cause ulcers.

6. The correct answer is c. Pepsin is an enzyme that causes mucosal injury in the intestine; all of the other choices protect the mucosa.

7. The correct answer is b. The exact mechanism is not known, but it is thought that H. pylori releases toxins that produce an inflammatory response. This in turn damages tissues, allowing ulcer formation to occur.

8. The correct answer is c. The etiology of IBS is not known, but studies have consistently shown that those with the syndrome respond to low levels of stimuli. The response produces increased motility, spasms, bloating, and discomfort.

9. The correct answer is b. There is no causal relationship between psychiatric disorders and IBS. However, the central nervous system when stimulated by fear, sadness, anger, and so on produces a variety of gastrointestinal symptoms such as nausea, vomiting, diarrhea, and pain. People who experience panic attacks, have high anxiety, or are sad or fearful have their central nervous systems overstimulated for long periods of time and, as a result, are likely to have such symptoms. If they have a hypersensitive gut, they can have a recurrent and prolonged response and IBS symptoms. Women who have been assaulted have been found to have a higher incidence of IBS than the general population. This is probably due to the long-term psychological trauma caused by such assaults. This places continued stress on the central nervous system and all other body systems.

10. The correct answer is a. Ulcerative colitis is characterized by abrupt onset and bloody diarrhea plus abdominal pain. There is a familial tendency to develop the disease. Tenesmus is the term for discomfort caused by inflammation of the rectum, producing a feeling of incomplete emptying of the bowel. Some people with ulcerative colitis find that eating fresh fruits and vegetables exacerbates the symptoms.

11. The correct answer is d. Management of Crohn’s disease includes all of those listed plus antispasmodics, immunosuppressive, and bulk agents, depending on the type and severity of symptoms.

12. The correct answer is d. The exact cause in unknown, but it is believed that diverticula develop in individuals with chronic constipation due to a lack of dietary fiber; hard stools require extra effort and higher intraluminal pressures for passage. This encourages a weak abdominal wall to pouch out, forming diverticula.

13. The correct answer is d. Any of these complications can happen depending on the size of the infection and whether or not it ruptures as a result of the inflammatory process.

14. The correct answer is a. Failure to move abdominal contents along results in vomiting and the inability of fluids to reach the colon, where fluid absorption occurs. Some fluids are lost through vomiting and more from inability of the body to absorb it.

15. The correct answer is d. Bacterial acute gastroenteritis is not contagious because it is an ingested toxin, and only those consuming contaminated food or water will become ill.