Inflammation and Repair Practice Questions

Q: Which of the following conditions is characterized by caseating granulomas?

Histoplasmosis. Explanation: The hallmark of certain chronic inflammatory conditions is the formation of **granulomas**. These are categorized into **caseating** (central "cheese-like" necrosis) and **non-caseating** (no central necrosis). **1. Why Histoplasmosis is correct:** Histoplasmosis, caused by the fungus *Histoplasma capsulatum*, is a classic cause of **caseating granulomas**. In the lungs and lymph nodes, it mimics Tuberculosis by producing necrotic centers within the granuloma. While TB is the most common cause of caseation, fungal infections like Histoplasmosis and Coccidioidomycosis can also present this way; however, in the context of standard medical examinations, Histoplasmosis is a high-yield fungal representative for caseation. **2. Why the other options are incorrect:** * **Sarcoidosis:** This is the classic prototype for **non-caseating granulomas**. The absence of central necrosis is a key diagnostic feature used to differentiate it from Tuberculosis. * **Coccidioidomycosis:** While it can occasionally show caseation, it more typically presents with pyogenic or non-caseating granulomatous responses containing characteristic **spherules** filled with endospores. * **All of the above:** Incorrect because Sarcoidosis strictly produces non-caseating granulomas. **NEET-PG High-Yield Pearls:** * **Caseating Granuloma:** Think Tuberculosis (most common), Histoplasmosis, and Lepromatous Leprosy (rarely). * **Non-Caseating Granuloma:** Think Sarcoidosis, Crohn’s disease, Berylliosis, and Cat-scratch disease. * **Histology Tip:** Look for "Schaumann bodies" and "Asteroid bodies" in Sarcoidosis (though not pathognomonic). * **Histoplasma Identification:** On silver stain (GMS), look for small, intracellular budding yeasts within macrophages.

Q: All of the following are true regarding the Arachidonic acid (AA) pathway, except:

Leukotrienes C4, D4 cause vasodilation.. **Explanation:** The Arachidonic Acid (AA) pathway is a central theme in inflammation and pharmacology. This question tests the physiological effects of eicosanoids and the mechanism of AA release. **Why Option D is the correct (False) statement:** Leukotrienes **C4, D4, and E4** (collectively known as cysteinyl leukotrienes) are potent **vasoconstrictors** and **bronchoconstrictors**. They also increase vascular permeability (leading to edema). In contrast, Prostaglandins like $PGI_2$ (Prostacyclin) and $PGE_2$ are the primary mediators that cause vasodilation in this pathway. **Analysis of other options:** * **Option A:** Aspirin is a non-selective, irreversible inhibitor of **Cyclooxygenase (COX-1 and COX-2)**. By inhibiting these enzymes, it prevents the conversion of AA into Prostaglandins and Thromboxanes, thus inhibiting a major branch of the AA pathway. * **Option B:** The rate-limiting step in eicosanoid synthesis is the release of AA from membrane phospholipids. This is mediated by the enzyme **Phospholipase A2 (PLA2)**, which is activated by an increase in **cytosolic $Ca^{2+}$** levels. * **Option C:** Phospholipase A2 acts on membrane phospholipids (like phosphatidylcholine) to cleave and release free **Arachidonic acid**, which then serves as the substrate for COX and LOX enzymes. **NEET-PG High-Yield Pearls:** 1. **LTC4, LTD4, LTE4:** Potent bronchoconstrictors; involved in the pathogenesis of asthma (Slow Reacting Substance of Anaphylaxis - SRS-A). 2. **LTB4:** Primarily involved in **chemotaxis** (attracts neutrophils). 3. **Zileuton:** Inhibits 5-Lipoxygenase (5-LOX), preventing leukotriene synthesis. 4. **Montelukast/Zafirlukast:** Block CysLT1 receptors (antagonists for LTC4, D4, E4). 5. **Steroids:** Inhibit the entire AA pathway by inducing **Lipocortin (Annexin A1)**, which inhibits Phospholipase A2.

Question 1

Lipoxins synthesized from arachidonic acid act by?

Accepted Answer

Decreasing leucocyte migration, adhesion, and chemotaxis

Answer

Increasing leucocyte migration, adhesion, and chemotaxis

Answer

Vasoconstriction

Answer

Increased vascular permeability

Question 2

Which of the following cellular components is capable of recognizing dead material?

Accepted Answer

Inflammasome

Answer

NET (Neutrophil Extracellular Traps)

Answer

Necrosis

Answer

Toll-like receptor

Question 3

Leukotrienes cause all of the following effects, EXCEPT:

Accepted Answer

Vasodilation

Answer

Vasoconstriction

Answer

Increased vascular permeability

Answer

None of the above

Question 4

Which of the following selectins is expressed in both platelets and endothelium?

Accepted Answer

Selectin P

Answer

Selectin L

Answer

Selectin E

Answer

None of the above

Question 5

What is the difference between primary and secondary wound healing?

Accepted Answer

More granulation tissue and fibrosis are seen in secondary healing.

Answer

Scarring is more cosmetic in secondary healing.

Answer

Secondary healing occurs faster.

Answer

Surgical wounds commonly heal by secondary healing.

Question 6

What is the arrangement of the nuclei in giant cells?

Accepted Answer

Arranged around the periphery

Answer

Present at the center

Answer

Forming a network

Answer

Arranged radially

Question 7

Which of the following conditions is characterized by caseating granulomas?

Accepted Answer

Histoplasmosis

Answer

Sarcoidosis

Answer

Coccidioidomycosis

Answer

All of the above

Question 8

Granuloma is characterized by all of the following except:

Accepted Answer

A reaction of acute inflammation

Answer

A specific type of chronic inflammation

Answer

Accumulation of modified macrophages

Answer

Initiated by a number of infectious and non-infectious agents

Question 9

All of the following are true regarding the Arachidonic acid (AA) pathway, except:

Accepted Answer

Leukotrienes C4, D4 cause vasodilation.

Answer

Aspirin inhibits the arachidonic acid pathway.

Answer

Cytosolic Ca2+ leads to activation of membrane phospholipase A2.

Answer

Action of phospholipase A2 causes synthesis of arachidonic acid.

Question 10

What is the principal mediator of vasodilation in acute inflammation?

Accepted Answer

Histamine

Answer

Serotonin

Answer

IL-1

Answer

TNF

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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