A tumor producing large amounts of gastrin DOES NOT include:

Correct Answer: B

Rationale: The correct answer is B: Hyperplasia of gastric mucosal lymphocytes. In a tumor producing large amounts of gastrin, hyperplasia of gastric epithelium (choice A) is expected due to increased gastrin stimulation. Excessive gastric acid secretion (choice C) is also expected as gastrin stimulates acid production. Histamine secretion in the gastric mucosa (choice D) can occur as histamine is released in response to gastrin. However, hyperplasia of gastric mucosal lymphocytes (choice B) is not a direct consequence of increased gastrin levels. Lymphocyte hyperplasia is more commonly associated with chronic inflammation or infection rather than gastrin overproduction.

Correct Answer: C

Rationale: Rationale: 1. Gastric phase starts when food enters the stomach. 2. Chemoreceptors detect bolus composition to initiate gastric secretions. 3. This detection triggers release of gastric juices for digestion. 4. Neural stimulation also occurs during gastric phase, but not exclusively. 5. Contractility increases during gastric phase for mixing and churning. In summary, choice C is correct as chemoreceptors detect bolus composition during the gastric phase, while the other choices are incorrect because they do not accurately reflect the physiological processes during this phase.

Correct Answer: C

Rationale: The correct answer is C: small intestine. Primary carcinoma is least common in the small intestine compared to the other choices. This is because the small intestine has a lower incidence of cancer compared to the esophagus, stomach, and colon. Factors contributing to this lower incidence include less exposure to carcinogens, a relatively smaller surface area, and less common inflammatory conditions that can lead to cancer development. Additionally, the small intestine has a more rapid turnover of cells, reducing the likelihood of cancerous mutations accumulating. Therefore, the small intestine is the least common site for primary carcinoma among the options provided.

Correct Answer: B

Rationale: The correct answer is B because the normal concentration of bilirubin in the plasma is about 0.8 gm%, which is a commonly accepted fact in medicine. Bilirubin is a product of hemoglobin breakdown and is typically measured in the blood to assess liver function and detect certain medical conditions. A, C, and D are incorrect: A: Myenteric plexus controls GIT motility, not secretion. C: Submucosal plexus controls GIT secretion, not motility. D: Pepsinogen activation needs hydrochloric acid (HCl) in the stomach, not calcium.

Correct Answer: B

Rationale: Step 1: CCK (Cholecystokinin) is released in response to the presence of fats and proteins in the small intestine. Step 2: CCK inhibits stomach motility to allow enough time for the gallbladder to release bile. Step 3: This slowing down of stomach motility aids in the digestion and absorption of fats. Step 4: Choices A, C, and D are incorrect as CCK does not directly affect gastric secretion, pancreatic enzyme secretion, or increase pancreatic secretions rich in bicarbonate.