Inflammation and Repair Practice Questions

Q: Which prostaglandin is primarily responsible for fever?

PGE2. **Explanation:** **Why PGE2 is the correct answer:** Prostaglandin E2 (PGE2) is the ultimate mediator of fever. During inflammation or infection, exogenous pyrogens (like bacterial LPS) stimulate immune cells to release endogenous pyrogens, primarily **IL-1 and TNF**. These cytokines travel to the hypothalamus, where they induce the enzyme **Cyclooxygenase (COX)** to convert arachidonic acid into **PGE2** [1]. PGE2 then acts on the EP3 receptors in the preoptic area of the hypothalamus, triggering a reset of the thermoregulatory set-point to a higher level, resulting in fever. This is the physiological basis for using NSAIDs (COX inhibitors) as antipyretics. **Analysis of Incorrect Options:** * **PGD2:** Primarily produced by mast cells; it is a potent chemoattractant for neutrophils and causes vasodilation and increased vascular permeability, but it does not mediate fever. * **PGF2α:** Primarily involved in uterine contractions (oxytocic effect) and bronchoconstriction. It is not a mediator of the systemic inflammatory response like fever. * **PGI2 (Prostacyclin):** Produced by vascular endothelium; it is a potent vasodilator and an inhibitor of platelet aggregation. While it contributes to the "pain" and "redness" of inflammation, it is not the primary pyrogen. **High-Yield NEET-PG Pearls:** * **PGE2 Triple Threat:** Remember PGE2 for **P**ain, **P**yrexia (Fever), and **P**atency of the Ductus Arteriosus [1]. * **Cytokine Trigger:** IL-1 is the most potent cytokine inducer of PGE2 in the hypothalamus [1]. * **Aspirin Mechanism:** Aspirin reduces fever by inhibiting COX-1 and COX-2, thereby blocking the synthesis of PGE2. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 101.

Question 1

Which prostaglandin is primarily responsible for fever?

Accepted Answer

PGE2

Answer

PGD2

Answer

PGF2a

Answer

PGI2

Question 2

Which of the following infections is associated with persistent neutrophil recruitment even after 24 hours of infection?

Accepted Answer

Pseudomonas

Answer

Tuberculosis

Answer

Virus

Answer

Protozoa

Question 3

A 25-year-old woman presents with a 2-week history of febrile illness and chest pain. She has an erythematous, macular facial rash and tender joints, particularly in her left wrist and elbow. A CBC shows mild anemia and thrombocytopenia. Corticosteroids are prescribed for the patient. The patient is noted to have increased serum levels of ceruloplasmin, fibrinogen, 2-macroglobulin, serum amyloid A protein, and C-reactive protein. Together, these markers belong to which of the following families of proteins?

Accepted Answer

Acute phase proteins

Answer

Anaphylatoxins

Answer

Inhibitors of platelet activation

Answer

Protease inhibitors

Question 4

Which reactant generated by neutrophils plays an important role in bacterial killing?

Accepted Answer

Superoxide anion

Answer

NADPH oxidase

Answer

Hexose monophosphate shunt

Answer

G proteins

Question 5

All of the following are positive acute phase reactants except which one?

Accepted Answer

Albumin

Answer

Serum amyloid A (SAA)

Answer

C-reactive protein (CRP)

Answer

Fibrinogen

Question 6

Free radicals are generated by all except?

Accepted Answer

Pseudopod extension

Answer

FC and C3b

Answer

Receptor mediated endocytosis

Answer

Respiratory burst

Question 7

Delayed prolonged leakage following tissue injury is due to:

Accepted Answer

Direct effect of the injuring agent

Answer

Cytokine-mediated vasodilation

Answer

Histamine

Answer

Endothelial retraction

Question 8

Which one of the following statements about chemical mediators of inflammation is NOT true?

Accepted Answer

Prostaglandins cause vasodilation at the site of inflammation.

Answer

Leukotrienes are formed by the lipoxygenase pathway.

Answer

Histamine is a preformed chemical mediator.

Answer

Thromboxane A2 is associated with platelet aggregation.

Question 9

Chemotaxis in response to activation of cells results in what type of movement?

Accepted Answer

Unidirectional motion

Answer

Random multidirectional movement

Answer

Adhesion to endothelium

Answer

Augmented oxygen dependent bactericidal effect

Question 10

Which one of the listed statements is the best histologic definition of an abscess?

Accepted Answer

A circumscribed collection of neutrophils with necrotic cellular debris

Answer

A localized defect that results from the sloughing of necrotic inflammatory tissue from the surface of an organ

Answer

A localized proliferation of fibroblasts and small blood vessels

Answer

An aggregate of two or more activated macrophages

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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