Inflammation and Repair Practice Questions

Q: Which of the following is an inhibitor of inflammation?

Lipoxin. The correct answer is **Lipoxin**. **Why Lipoxin is the correct answer:** Inflammation is a tightly regulated process that includes "stop signals" to prevent tissue damage. **Lipoxins (LXA4 and LXB4)** are endogenous anti-inflammatory mediators derived from arachidonic acid via the lipoxygenase pathway. Unlike pro-inflammatory leukotrienes, lipoxins are produced through **platelet-leukocyte interactions** (transcellular biosynthesis). Their primary functions include: * Inhibiting neutrophil chemotaxis and adhesion to endothelium [1]. * Stimulating the recruitment of non-phlogistic (non-inflammatory) monocytes. * Promoting the clearance of apoptotic cells (efferocytosis) by macrophages, thereby signaling the **resolution phase** of inflammation. **Why the other options are incorrect:** * **Histamine:** A vasoactive amine released by mast cells [1]. It is a potent **pro-inflammatory** mediator responsible for vasodilation and increased vascular permeability during the immediate phase of acute inflammation [1]. * **Leukotrienes (LTB4, LTC4, LTD4, LTE4):** These are **pro-inflammatory** metabolites of arachidonic acid [1]. LTB4 is a powerful chemoattractant for neutrophils, while the cysteinyl leukotrienes (C4, D4, E4) cause bronchospasm and increased vascular permeability [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 95-101.

Q: Which chemical mediators are known to cause fever?

All of the above. **Explanation:** Fever (pyrexia) is a systemic manifestation of inflammation regulated by the hypothalamus [1]. The process is driven by **pyrogens**, which can be exogenous (e.g., bacterial LPS) or endogenous (cytokines). 1. **IL-1 and TNF (Options A & B):** These are the primary **endogenous pyrogens** [1]. When macrophages and other immune cells are activated, they release IL-1 and TNF into the circulation. These cytokines travel to the hypothalamus, specifically the *organum vasculosum of the lamina terminalis* (OVLT). 2. **Prostaglandins (Option C):** IL-1 and TNF stimulate the enzyme **Cyclooxygenase (COX)**, which converts arachidonic acid into **Prostaglandin E2 (PGE2)**. PGE2 acts on the thermoregulatory center of the anterior hypothalamus to "reset" the body’s temperature set-point to a higher level, resulting in fever [1]. **Why "All of the above" is correct:** The pathway follows a cascade: **IL-1/TNF → COX activation → PGE2 production → Fever.** Since all three mediators are essential components of this thermoregulatory shift, they are all correctly identified as mediators of fever [1]. **High-Yield NEET-PG Pearls:** * **PGE2** is the specific prostaglandin most directly responsible for raising the hypothalamic set-point [1]. * **Mechanism of Antipyretics:** NSAIDs (like Aspirin or Paracetamol) reduce fever by inhibiting the COX enzyme, thereby blocking the synthesis of PGE2. * **Other Systemic Effects:** Besides fever, IL-1 and TNF also stimulate the liver to produce **Acute Phase Reactants** (e.g., CRP, Fibrinogen, Serum Amyloid A). * **IL-6** is another major cytokine involved in the systemic inflammatory response and induction of fever. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 101.

Question 1

A 60-year-old male patient complains of discoloration of his right leg. He is a known case of diabetes mellitus. Physical examination reveals blackish discoloration of the right leg with a dry and shrunken appearance. Which of the following most appropriately describes the condition of this patient?

Accepted Answer

Dry gangrene

Answer

Wet gangrene

Answer

Psoriasis

Answer

Pemphigus

Question 2

Which of the following is an inhibitor of inflammation?

Accepted Answer

Lipoxin

Answer

Histamine

Answer

Leukotriene

Answer

None of the above

Question 3

The process by which red blood cells move out of vessels through widened inter endothelial junction is referred to as:

Accepted Answer

Diapedesis

Answer

Pavementing

Answer

Rouleaux formation

Answer

Chemotaxis migration

Question 4

All of the following are characteristic of exudates EXCEPT:

Accepted Answer

Protein content less than 1 gm/dL

Answer

Predominantly polymorphonuclear cells

Answer

Specific gravity greater than 1.015

Answer

Turbid appearance of the fluid

Question 5

Which of the following is an endogenous chemoattractant?

Accepted Answer

C5a

Answer

Bacterial products

Answer

Lipopolysaccharide A

Answer

C8

Question 6

Which of the following is NOT a labile cell?

Accepted Answer

Hepatocytes

Answer

Bone marrow

Answer

Epidermal cells

Answer

Small intestine mucosa

Question 7

Neovascularization is maximum on which day?

Accepted Answer

5th day

Answer

3rd day

Answer

7th day

Answer

10th day

Question 8

Which of the following causes the maximum effect in myocardial reperfusion injury?

Accepted Answer

Free radicals

Answer

Neutrophil

Answer

Monocytes

Answer

Eosinophils

Question 9

In chronic granulomatous inflammation, which of the following processes is most likely to predominate?

Accepted Answer

Proliferation

Answer

Exudation

Answer

Congestion

Answer

Transudation

Question 10

Which chemical mediators are known to cause fever?

Accepted Answer

All of the above

Answer

Interleukin-1 (IL-1)

Answer

Tumor Necrosis Factor (TNF)

Answer

Prostaglandins

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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