Pathology of the GI Tract- SI and Colon (3) Flashcards
what is the role of G cells in the antral glands?
they release gastrin to stimulate luminal acid secretion by parietal cells within the gastric fundus and body
when is gastrin released?
in response to vagal and gastrin-releasing peptide (GRP) stimulation secondary to ingestion of peptides, amino acids, gastric distention, and an elevated stomach pH
when is gastrin release decreased?
in response to paracrine inhibition by somatostatin and decreased stomach pH
most gastric adenocarcinomas involve what?
the gastric antrum; the lesser curvature is involved more often than the greater curvature
what nerve mediates acid stimulatory effects in the stomach?
vagus nerve
what are 2 congenital abnormalities of the stomach that we discussed?
pyloric stenosis and ectopia
what happens when ectopic pancreatic tissue is present in the pylorus?
inflammation and scarring may lead to obstruction (they can mimic invasive cancer)
what is acute gastritis?
a mucosal inflammatory process; when neutrophils are present, the lesion is referred to as acute gastritis; when inflammatory cells are rare or absent, the term gastropathy is used
where are prostaglandins found in high numbers?
in the gastric mucosa and gastric juice
when are stress ulcers most common?
in individuals with shock, sepsis, or severe trauma
what are curling ulcers?
ulcers occurring in the proximal duodenum and associated with severe burns or trauma
what are cushing ulcers?
gastric, duodenal, and esophageal ulcers arising in persons with intracranial disease; they carry a high incidence of perforation
what are 2 etiologies for chronic gastritis?
infection with h. pylori; autoimmune gastritis
what is the most common cause of chronic gastritis?
infection with the bacillus helicobacter pylori
what can long-standing chronic gastritis that involves the body and fundus lead to?
it may ultimately lead to mucosal atrophy and/or intestinal metaplasia–> both are risk factors for adenocarcinoma
what does chronic gastritis expose the epithelium to?
inflammation-related free radical damage and proliferative stimuli leading to gastric dysplasia–> over time this can result in carcinoma
how does h. pylori present? (like how does the stomach look)
most often presents as predominantly antral gastritis with normal or increased acid production
what is H. pylori infection associated with in the US?
poverty, household crowding, limited education, african american or mexican american ethnicity, residence in rural areas, and birth outside of the US
what is the carrier of h. pylori?
humans are the primary carriers, suggesting that transmission is primarily by the fecal-oral route
what are three examples of the diagnostic tests used for H. pylori infections?
serologic test, fecal bacterial antigen detection, urea breath test
what are the effective treatments for H. pylori?
combinations of antibiotics and proton pump inhibitors
what is autoimmune gastritis characterized by? histologically
diffuse mucosal damage of the oxyntic (acid-producing) mucosa within the body and fundus
what is autoimmune gastritis characterized by in general?
antibodies to parietal cells and intrinsic factor that can be detected in serum and gastric secretions; reduced serum pepsinogen I concentration; endocrine cell hyperplasia; vitamin B12 deficiency; defective gastric acid secretion (achlorhydria)
what is progression of autoimmune gastritis like?
progression to gastric atrophy probably occurs over 2-3 decades, and anemia is seen in only a few patients; because of the slow onset and variable progression, patients are generally diagnosed only after being affected for many years
