Gastrointestinal Pathology Practice Questions

Q: The greatest volume of gastric secretion occurs during which phase?

Gastric phase. The secretion of gastric acid occurs in three distinct phases, categorized by the location of the stimulus. **Correct Answer: B. Gastric phase** The **gastric phase** accounts for approximately **50-60%** of the total gastric acid secretion. It is triggered by the arrival of food in the stomach, which causes **distension** (activating vagovagal and local enteric reflexes) and the presence of **peptides/amino acids** (stimulating G-cells to release Gastrin) [1]. This phase provides the greatest volume of secretion because the physical presence of food provides a sustained stimulus for both hormonal and neural pathways. **Explanation of Incorrect Options:** * **A. Cephalic phase:** This phase accounts for about **30%** of secretion. It is triggered by the sight, smell, or thought of food via the Vagus nerve. While it prepares the stomach, it does not produce the bulk of the volume. * **C. Intestinal phase:** This phase accounts for only **5-10%** of secretion. It begins when chyme enters the duodenum. While initially stimulatory (via intestinal gastrin), it quickly becomes inhibitory (via secretin and CCK) to prevent over-acidification of the duodenum. * **D. Deglutition:** This refers to the act of swallowing. While it is part of the digestive process, it is a mechanical action and not a physiological "phase" of gastric acid secretion. **High-Yield Facts for NEET-PG:** * **Gastrin** is the most potent stimulator of the gastric phase [1]. * **Vagus nerve** is the primary mediator of the cephalic phase (blocked by vagotomy). * **Sham feeding** is an experimental method used to study the cephalic phase. * **pH < 1.5** in the antrum inhibits gastrin release (negative feedback) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 349-352.

Q: What is the most common site for diverticula?

Sigmoid colon. **Explanation:** **Diverticulosis** refers to the herniation of mucosa and submucosa through the muscular layers of the colon (pseudodiverticula). **1. Why Sigmoid Colon is the Correct Answer:** The sigmoid colon is the most common site (involved in >90% of cases) due to **Laplace’s Law**. This law states that pressure is inversely proportional to the radius ($P = T/r$). Since the sigmoid has the smallest diameter of the colon, it generates the highest intraluminal pressures [1]. Additionally, the sigmoid acts as a "reservoir" where stool is most dehydrated and firm, requiring high-pressure contractions to move it forward [1]. These high pressures force the mucosa through weak points in the muscularis propria—specifically where the **vasa recta** (nutrient arteries) penetrate the muscle wall. **2. Analysis of Incorrect Options:** * **B. Ileum:** True diverticula (like Meckel’s) can occur here, but acquired pulsion diverticula are rare in the small intestine compared to the colon. * **C & D. Ascending and Transverse Colon:** While diverticula can occur here (more common in Asian populations), they are statistically less frequent than sigmoid involvement in global and Indian contexts. **High-Yield Clinical Pearls for NEET-PG:** * **Pathogenesis:** Associated with **low-fiber diets**, which decrease stool bulk and increase the pressure required for peristalsis [1]. * **Complications:** The most common cause of massive **painless lower GI bleeding** in the elderly [1]. If inflamed (**Diverticulitis**), it presents as "Left-sided appendicitis." * **Imaging:** Contrast CT is the gold standard for acute diverticulitis; Colonoscopy is contraindicated in the acute phase due to perforation risk. * **Associated Condition:** **Saint’s Triad** (Diverticulosis + Hiatus Hernia + Gallstones). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 370-371.

Question 1

A 55-year-old man presents with recurrent epigastric pain. Upper GI endoscopy and gastric biopsy reveal a neoplastic, lymphocytic infiltrate invading glandular tissue. Giemsa staining is positive for Helicobacter pylori. Which of the following is the most likely diagnosis?

Accepted Answer

Marginal zone lymphoma

Answer

Burkitt lymphoma

Answer

Follicular lymphoma

Answer

Mantle cell lymphoma

Question 2

Which of the following is FALSE about hypertrophic gastropathy?

Accepted Answer

Can produce MALTomas

Answer

Seen in Menetrier's disease and Zollinger-Ellison syndrome (ZES)

Answer

Associated with malignancy

Answer

Shows cerebriform rugacity on endoscopy

Question 3

The greatest volume of gastric secretion occurs during which phase?

Accepted Answer

Gastric phase

Answer

Cephalic phase

Answer

Intestinal phase

Answer

Deglutition

Question 4

Peptic ulcer is caused by which of the following microorganisms?

Accepted Answer

Helicobacter pylori

Answer

Campylobacter jejuni

Answer

Pneumocystis carinii

Answer

Cryptosporidium

Question 5

What is the most common site for diverticula?

Accepted Answer

Sigmoid colon

Answer

Ileum

Answer

Ascending colon

Answer

Transverse colon

Question 6

Which anomaly is seen in the following clinical condition?

Accepted Answer

Dental fusion

Answer

Gemination

Answer

Concrescence

Answer

Supernumerary teeth

Question 7

A child presents with generalized "freckling" affecting the buccal mucosa, lips, palms, soles, and sun-unexposed skin. Which of the following additional findings would most likely be present?

Accepted Answer

Colonic polyps

Answer

Desmoid tumors

Answer

Epidermoid cysts

Answer

Osteomas of the jaw

Question 8

Leukoplakia appears white due to which of the following mechanisms?

Accepted Answer

Cornified layer which imbibes water.

Answer

Thick epithelium.

Answer

Underlying connective tissue.

Answer

All of the above.

Question 9

Which of the following are true about celiac disease?

Accepted Answer

Crypt hyperplasia

Answer

Villous atrophy

Answer

Infiltration of lymphocytes

Answer

Cryptitis

Question 10

Linear enamel caries is also known as:

Accepted Answer

Odontoclasia

Answer

Occult caries

Answer

Fluoride bomb

Answer

None of the above

Gastrointestinal Pathology — MCQs

Gastrointestinal Pathology — MCQs

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