An endoscopic biopsy of gastric mucosa reveals small intestinal type epithelium. This finding is most likely due to:

Correct Answer: B

Rationale: The correct answer is B: congenital heterotopia. This is because the presence of small intestinal type epithelium in the gastric mucosa indicates ectopic tissue that is not normally found in the stomach. This condition is known as congenital heterotopia, where tissues from one organ are found in another due to developmental abnormalities. A: Chronic gastritis would not lead to the presence of small intestinal type epithelium in the gastric mucosa. C: Precancerous dysplasia refers to abnormal cellular changes that can progress to cancer but does not explain the presence of small intestinal type epithelium. D: Metastatic carcinoma would involve the spread of cancer cells from another primary site, not the presence of ectopic tissue.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Saliva is slightly acidic, not alkaline. 2. The secretion of saliva is under both neural and hormonal control. 3. Saliva contains enzymes that digest carbohydrates, not proteins. 4. Therefore, choice C is correct as it provides accurate information about the alkalinity of saliva.

Correct Answer: A

Rationale: The correct answer is A because only the calcium-containing antacid may increase gastric acid secretion. This is because calcium-containing antacids can stimulate the release of gastrin, which in turn increases gastric acid secretion. Choices B, C, and D are incorrect because cimetidine, not a calcium-containing antacid, is the one that can cause an increase in urinary pH, produce a laxative effect, and prevent the rise in gastric pH after a meal, respectively. Therefore, A is the only statement that accurately distinguishes between cimetidine and a calcium-containing antacid in the context of treating peptic ulcers.

Correct Answer: D

Rationale: The correct answer is D: Colon. The colon is not a part of the small intestine; it is part of the large intestine. The small intestine consists of three parts: the duodenum, jejunum, and ileum. The duodenum is the first segment of the small intestine, followed by the jejunum and then the ileum. The colon, also known as the large intestine, comes after the small intestine in the digestive system. Therefore, the colon is not a part of the small intestine, making choice D the correct answer.

Correct Answer: D

Rationale: The correct answer is D: Cobalamin (vitamin B12) deficiency. After a total gastrectomy, the patient lacks the intrinsic factor needed for vitamin B12 absorption in the ileum, leading to deficiency. This can result in megaloblastic anemia, neurological symptoms, and fatigue. A: Constipation is not typically associated with total gastrectomy. B: Dehydration may occur postoperatively but is not a specific consequence of total gastrectomy. C: Elevated total serum cholesterol is not a direct effect of total gastrectomy.