It’s Friday morning and Sal Volpe is sitting in Dr. Lorraine’s exam room, dozing

ID: 220271 • Letter: I

Question

It’s Friday morning and Sal Volpe is sitting in Dr. Lorraine’s exam room, dozing after another night of disrupted sleep. When the doctor knocks and walks in, she finds the 66-year-old man looking exhausted and uncomfortable. Sal gets to the reason for his visit immediately: He’s been suffering from “stomach aches” (dyspepsia) that wake him at night and nag him in between meals during the day. He describes his pain as gnawing, burning (maybe a 4 out of 10 on a pain scale) and points to the epigastric region of his abdomen. When he eats, he tells Dr. Lorraine, the pain goes away, but then he feels bloated and a little nauseated. The pain usually returns 2–4 hours later, depending on what he eats. Sal explains that he has had some pain relief from the over-the-counter drug Pepcid® (famotadine).

Dr. Lorraine proceeds with the history and physical exam. She discovers that Sal has a family history for gastrointestinal cancer and has unintentionally lost 10 pounds since his checkup a year ago. His epigastric area is modestly tender to palpation. She suspects a peptic ulcer (gastric or duodenal), but the weight loss and family history make it prudent to eliminate the diagnosis of stomach (gastric) cancer. “Mr. Volpe, I think you may have a stomach or intestinal ulcer,” Dr. Lorraine says. “I suggest we perform an endoscopy to have a look. This involves passing a small tube with a small camera through your mouth and into your stomach. We can look at the wall of your stomach and small intestine, check for an ulcer, and remove a very small piece of tissue to test for infection. We call this a biopsy. We’ll also test the biopsy for cancer because of your family history. But, I really think we’re dealing with an ulcer here and not cancer.”

Later that month, the endoscopy is performed and it confirms Dr. Lorraine’s suspicions. Sal has a duodenal ulcer and infection with the bacterium Helicobacter pylori (H. pylori). This is not surprising since H. pylori is the cause of most peptic ulcer disease, particularly in the duodenum. Treatment involves complete eradication of the H. pylori with two different antibiotics, and a drug that decreases gastric acid secretion, a so-called proton pump inhibitor (PPI). Dr. Lorraine explains to Sal, “Mr. Volpe, you do not have stomach cancer, but you do have a duodenal ulcer caused by the H. pylori bacteria I was telling you about. Too much acid and inflammation from this infection is causing your pain. The good news is we can probably cure your ulcer by killing the bacteria, but you will have to take three different medications twice a day for 14 days. I’ll see you again in 3 weeks; we can do a simple breath test to determine if the H. pylori has been successfully eliminated.”

Short Answer Questions:

The structures in the epigastric region share a common nerve supply. Can you name the specific cranial nerve that serves this region and the part of the nervous system to which it belongs?

In order to understand the disease in Mr. Volpe’s alimentary canal, one must know the layers that make up its walls. Design a chart that identifies the four basic layers of the alimentary canal, the tissues that make up each layer, and the general function of each layer.

Dr. Lorraine suspects a peptic ulcer. This is an inflammatory lesion in the stomach or duodenal mucosa, which may extend through all layers of the alimentary canal wall. Describe the basic histological (tissue) structure of the mucosa layer in the alimentary canal. Identify the unique features of the mucosa in the stomach and in the duodenum, and explain how this uniqueness determines the function of the stomach and the duodenum.

Mr. Volpe asks, “What do the bacteria have to do with the ulcer?” Dr. Lorraine tells him that the H. pylori increases stomach acid secretion and, at the same time, breaks down the lining of your stomach and duodenum. What is the source and normal function of acid in the stomach and what regulates its production

Why is Mr. Volpe’s dyspepsia relieved by food, and aggravated 2–4 hours after a meal?

Explanation / Answer

1.The structures in the epigastric region share a common nerve supply. Can you name the specific cranial nerve that serves this region and the part of the nervous system to which it belongs?

The specific Cranial nerve in the epigastric region is the vagus nerve, which runs from the medulla to the thorax and abdominal cavity which carries visceral sensory information from receptors located in the abdominal organs.

2.In order to understand the disease in Mr. Volpe’s alimentary canal, one must know the layers that make up its walls. Design a chart that identifies the four basic layers of the alimentary canal, the tissues that make up each layer, and the general function of each layer.

The four layers of the alimentary canal are:

mucosa

It is coated with simple columnar epithelium. It secretes mucus, enzymes and hormone; protects underlying layers; and absorbs digested end-products.

submucosa

It is composed of areolar connective tissue, surrounds the mucosa and contains blood and lymph vessels as well as nerves that serve nearby tissues.

muscularis externa

It is composed of smooth muscle that contributes to motility in the alimentary canal.

serosa

It is an epithelial-connective tissue membrane that anchors the alimentary canal in the abdominal cavity.

3.Dr. Lorraine suspects a peptic ulcer. This is an inflammatory lesion in the stomach or duodenal mucosa, which may extend through all layers of the alimentary canal wall. Describe the basic histological (tissue) structure of the mucosa layer in the alimentary canal. Identify the unique features of the mucosa in the stomach and in the duodenum, and explain how this uniqueness determines the function of the stomach and the duodenum.

The mucosal layer is composed of three layers, beginning with the innermost layer:

A basic mucosa is made up of simple columnar epithelium that is abundant in mucus-secreting cells, which provide a slippery, wet protective barrier from digestive enzymes, pathogens and other harmful substances.

In both the stomach and duodenum, this epithelial layer is highly regenerative for rapid repair.

In the stomach, the simple columnar epithelium contains many mucus cells; these cells produce a viscous, alkaline mucus that protects against the acidic gastric juices and pepsin.

The stomach mucosa also forms gastric pits that release a variety of secretions, which form gastric juice. In the duodenum, the mucosa forms villi – finger-like projections that line the epithelium with microvilli; this greatly enhances surface area.

The lamina propria is made of loose aerolar connective tissue with a rich capillary bed. Along with the mucosa, the lamina propria forms what is called the mucus membrane.

The muscularis mucosae is made of a thin layer of smooth muscle. It contributes the movement of the mucosa and the facilitation of secretions in both the stomach and duodenum.

4.Mr. Volpe asks, “What do the bacteria have to do with the ulcer?” Dr. Lorraine tells him that the H. pylori increases stomach acid secretion and, at the same time, breaks down the lining of your stomach and duodenum. What is the source and normal function of acid in the stomach and what regulates its production.

The parietal cells in gastric pits pump out hydrogen and chloride, which combine in the stomach to form the strong acid, HCl. HCl helps in digestion by denaturing food proteins, and breaking down plant cell walls.

As a protective mechanism, HCl kills many types of microorganisms. Secretion of HCl is under the regulation of the gastric reflex and the hormone gastrin. When food enters the stomach, baroreceptors are stretched and chemoreceptors detect protein and an increase in pH.

5.Why is Mr. Volpe’s dyspepsia relieved by food, and aggravated 2–4 hours after a meal?

When food enters the stomach it raises the pH of stomach contents, closes the pyloric sphincter, and inhibits duodenal secretions and motility.

The stomach begins secreting HCl and is typically empty of food about 2-4 hours after a meal, longer if the meal is high in fat. At night, circadian-mediated secretion of HCl is high.