Case Presentation Harold, a fifty-eight year old grocery store manager, hadrecently been waking up in the middle of the night with abdominalpain. This was happening several nights a week. He was alsoexperiencing 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 thenasked Harold some questions. He noted that Harold's appetite hadsuffered as a result of the pain he was experiencing and as aresult of the fear that what he was eating may be responsible forthe pain. Otherwise, Harold seemed fine. The doctor referred Harold to a physician that specialized ininternal medicine and had Harold make an appointment for aprocedure called an endoscopy. The endoscopy was performed at ahospital later that week. During the procedure, a long, thin tubewas inserted into Harold's mouth and directed into his digestivetract. The end of the tube was equipped with a light source and asmall camera which allowed the doctor to observe the interior ofHarold's stomach. The endoscope was also equipped with a smallclaw-like structure that the doctor could use in order to obtain asmall tissue sample from the lining of Harold's

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

Case Background

A peptic ulcer is a sore that occurs in the lining of a part ofthe gastrointestinal tract that is exposed to pepsin and acidsecretions. Most peptic ulcers occur in the lining of the stomachor duodenum. 90% of all duodenal ulcers and 80% of all gastriculcers are caused by H. pylori infection. Most of the remainingpeptic ulcers are caused by long-term usage of certainanti-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 infectedindividuals and may be spread via this fluid. H. pylori bacteriahave the ability to survive

the acid environment in the stomach because they produce enzymesthat neutralize stomach acids. They also have the ability to movethrough the mucous membrane lining the stomach or duodenum and takeup residence in the underlying connective tissue. The damage to themucous membrane that results from a H. pylori infection allowspepsin and hydrochloric acid to further damage the wall of thestomach 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 gastricjuice. (3x4=12 Marks)

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

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