University:
Stanford University
Course:
MED 101 | Human Anatomy
Academic year:

2023
Views:

13

Pages:

2
Author:

larbi43100

‭Peptic ulcer‬ ‭The gastric mucosa is divided into two main portions: fundic mucosa and‬ ‭antropyloric mucosa. In the first there are essentially mucus cells (synthesis of‬ ‭mucus and bicarbonates), parietal cells (synthesis of hydrochloric acid and‬ ‭intrinsic factor), principal cells (synthesis of pepsin and gastric lipase) and ECL‬ ‭cells. (histamine synthesis). In the second there are mucus cells, G cells (gastrin‬ ‭synthesis) and D cells (somatostatin synthesis). The secretion of hydrochloric‬ ‭acid by the stomach is the responsibility of the parietal cells. These are‬ ‭stimulated, directly or indirectly, by acetylcholine from postganglionic vagal‬ ‭fibers (which act on muscarinic cholinergic receptors carried by these cells), by‬ ‭gastrin (synthesized by G cells) and by histamine (synthesized by ECL cells).‬ ‭Prevalence‬‭-It is 6 to 15% for UD (duodenal ulcer)‬‭and approximately 4 times‬ ‭lower for UG (gastric ulcer). However, autopsy studies tend to demonstrate‬ ‭that the prevalence is comparable for the two locations.‬ ‭Impact‬‭-It is approximately 2/1000 for UD and 0.5/1000‬‭for UG.‬ ‭Sex ratio‬‭-UD affects men more than women (sex ratio‬‭= 3/1), the‬ ‭difference is less marked for UG.‬ ‭Age at diagnosis‬‭-UD has its peak incidence in the‬‭fifth decade (it is rare before‬ ‭the age of 15), while UG‬ ‭has its peak incidence in the sixth decade (it can however be‬ ‭observed from the age of 5).‬ ‭An ulcer is a mucosal breach of more than 5 mm in diameter which crosses the‬ ‭muscular mucosa and reaches at least the submucosa (whereas an erosion by‬ ‭definition only affects the mucosa).‬ ‭Duodenal ulcer‬‭-It is most often single, sits on the‬‭anterior surface of the‬ ‭duodenal bulb approximately 3 cm from the pyloroduodenal junction or‬ ‭upstream (90% of cases), is rounded in shape, and generally measures less‬ ‭than 10 mm in diameter (but it can reach up to 6 cm). Malignant duodenal‬ ‭ulcer is extremely rare.‬ ‭Gastric ulcer‬‭-It is most often single, preferentially‬‭located at the level of the‬ ‭antrum or the small gastric curvature, and has an average diameter slightly‬ ‭greater than that of the UD. Over time, UG is likely to become cancerous in‬ ‭approximately 10% of cases. Four types of UG are described according to‬ ‭their location and the acid secretion value:‬ ‭ ype I: in the gastric body, associated with low acid‬ T ‭secretion (hypochlorhydria);‬ ‭-‬ ‭Type II: at the level of the gastric antrum, associated with low or normal‬ ‭acid secretion;‬ -‭ ‬ ‭Type III: within 3 centimeters upstream of the pylorus, associated with‬ ‭normal or high acid secretion (hyperchlorhydria); Type IV: at the level‬ ‭-‬ ‭of the cardia, associated with hypochlorhydria.‬ ‭-‬ ‭The two main etiologies are‬‭Helicobacter pylori‬‭and‬‭nonsteroidal anti-‬ ‭inflammatory drugs.‬ ‭Helicobacter pylori‬‭-This small spiral bacillus, Gram-negative,‬‭produces a urease‬ ‭which hydrolyzes urea into ammonia and carbon dioxide. It is associated with 70‬ ‭to 90% of patients with DU and 70%‬