USMLE Forum Archives - USMLE Step 1 - Pathology 18
Pathology 18
TheOne - 10-15-06 16:02
Which of the following conditions would mostly likely be associated with chronic gastritis (Type A) resulting from autoimmune destruction of parietal cells?
A. Decreased growth of luminal bacteria
B. Decreased likelihood of developing gastric carcinoma
C. Decreased plasma concentration of gastrin
D. Increased production of macrocytic red blood cells
E. Increased secretion of pancreatic bicarbonate
TheOne - 10-15-06 16:02
Which of the following conditions would mostly likely be associated with chronic gastritis (Type A) resulting from autoimmune destruction of parietal cells?
A. Decreased growth of luminal bacteria
B. Decreased likelihood of developing gastric carcinoma
C. Decreased plasma concentration of gastrin
D. Increased production of macrocytic red blood cells
E. Increased secretion of pancreatic bicarbonate
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#1
correct
TheOne - 10-18-06 12:48 Explanation: The correct answer is D. Autoimmune destruction of parietal cells would lead to decreased secretion of gastric acid and intrinsic factor. The diminished availability of intrinsic factor would result in poor absorption of dietary vitamin B12. Over time, the vitamin B12 deficiency could lead to pernicious anemia, which is characterized by increased production of macrocytes (megaloblasts) by the bone marrow. Because of the decrease in gastric acid secretion, luminal bacteria (choice A) would most likely exhibit increased (not decreased) growth. One of the functions of HCl secreted by the parietal cells is to sterilize the gastric lumen. Patients with Type A gastritis have an increased likelihood of developing gastric carcinoma (not decreased, choice B). A decrease in acid secretion leads to increased secretion of gastrin (not decreased, choice C) by antral G cells. This is because low gastric pH (less than 3) inhibits gastrin secretion via paracrine release of somatostatin from cells in the gastric mucosa that can sense the acidity. With decreased parietal cells, the pH of the gastric lumen would rise and remove this inhibitory component. Because less acid would be delivered to the duodenum with parietal cell destruction, less secretin would be released into the blood.. This would result in decreased pancreatic bicarbonate secretion (not increased, choice E).
#2
Re: Pathology 18 galaxy - 05-27-10 19:17 Which of the following conditions would mostly likely be associated with chronic gastritis (Type A) resulting from autoimmune destruction of parietal cells?
D. Increased production of macrocytic red blood cells
#3
Re: Pathology 18 babbu5508 - 06-21-10 14:57 D. Increased production of macrocytic red blood cells due to decrease in the absorption of vitamin b12 by decrease in the intrinsic factor.
#4
Re: Pathology 18 bingousmle - 06-30-10 22:25 pernicious anemia will lead to less IF so less vitamin B12 which will lead to megaloblastic amemia soi ncreased production of macrocytic red blood cells
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