Question

Case Presentation Harold, a fifty-eight year old grocery store manager, had recently been waking up in the middle of the night with abdominal pain. This was happening several nights a week. He was also experiencing occasional discomfort in the middle of the afternoon. Harold decided to schedule an appointment with his physician. The doctor listened as Harold described his symptoms and then asked Harold some questions. He noted that Harold's appetite had suffered as a result of the pain he was experiencing and as a result of the fear that what he was eating may be responsible for the pain. Otherwise, Harold seemed fine. The doctor referred Harold to a physician that specialized in internal medicine and had Harold make an appointment for a procedure called an endoscopy. The endoscopy was performed at a hospital later that week. During the procedure, a long, thin tube was inserted into Harold's mouth and directed into his digestive tract. The end of the tube was equipped with a light source and a small camera which allowed the doctor to observe the interior of Harold's stomach. The endoscope was also equipped with a small claw-like structure that the doctor could use in order to obtain a small tissue sample from the lining of Harold's

stomach, if required. The endoscopy revealed that Harold had a peptic ulcer. Analysis of a tissue sample taken from the site showed that Harold also had an infection that was caused by Helicobacter pylori bacteria. The doctor who performed the endoscopy gave Harold prescriptions for two different antibiotics and a medication that would decrease the secretion of stomach acid. The doctor also instructed Harold to schedule an appointment for another endoscopy procedure in 6 months.

Case Background

A peptic ulcer is a sore that occurs in the lining of a part of the gastrointestinal tract that is exposed to pepsin and acid secretions. Most peptic ulcers occur in the lining of the stomach or duodenum. 90% of all duodenal ulcers and 80% of all gastric ulcers are caused by H. pylori infection. Most of the remaining peptic ulcers are caused by long-term usage of certain anti-inflammatory medications like aspirin.

There is still some question as to how H. pylori is spread. However, H. pylori has been identified in the saliva of infected individuals and may be spread via this fluid. H. pylori bacteria have the ability to survive

the acid environment in the stomach because they produce enzymes that neutralize stomach acids. They also have the ability to move through the mucous membrane lining the stomach or duodenum and take up residence in the underlying connective tissue. The damage to the mucous membrane that results from a H. pylori infection allows pepsin and hydrochloric acid to further damage the wall of the stomach or duodenum. The sore that results is the peptic ulcer.

Answer the following questions:

1.

1. Hydrochloric acid

2. Pepsinogen

3. Pepsin

4. Intrinsic factor

Describe the functions of the following components of gastric juice. (3x4=12 Marks)

2. Why don’t the components of gastric juice damage the wall of the stomach in the absence of a H. pylori infection? (4 Marks

3. Why don’t most other types of bacteria produce ulcers?

Answer 1

Describe the functions of the following components of gastric juice:

1. Hydrochloric acid: HCL triggers the production of pepsin which is essential for protein digestion. It also helps down in chemical break down of macromolecules. It helps for immune system by eliminating bacteria and viruses in the stomach thereby protecting your body from infection.

2. Pepsinogen:  Pepsinogen is a precursor molecule called as zymogen of pepsin which is critical for protein digestion.Pepsinogen is secreted by both mucous cells and chief cells. Inactive pepsinogen gets converted into active pepsin by the action of gastric acid.

3. Pepsin: Pepsin is an stomach protease which initiates protein digestion in the ingested food.

4. Intrinsic factor: Parietal cells of stomach secrete a glycoprotein called intrinsic factors which is cruicial for absorption of vitamin B12 unless cause pernicious anemia.

2.  Stomach lining is protected with mucous coat to prevent the action of HCL and its erosion. Despite this sophistication, it is possible to get ulcer and sore when there is an infection of H.pylori. It weakends the mucous coating of the stomach and duodenum and enable the stomach cells to the action of gastric secretion. The lesion can be initiated by H.pylori which can be exacerbated by the enzymes resulting in an ulcer.

. Heliobacter pylori is a bacterium that thrives in the highly acidic environment of the stomach. An H. pylori infection can start a lesion that HCl and digestive enzymes can exacerbate, resulting in an ulcer

3.  Often peptic ulcer is associated wiht the infection of H.pylori. Because of the highly acidic environment of the stomach but the H.pylori thrives to grow in such a acidic environment.