Inflammation and Repair Practice Questions

Q: The most important function of epithelioid cells in tuberculosis is -

Secretory. ***Secretory*** - Epithelioid cells are **modified macrophages** characterized by abundant eosinophilic cytoplasm due to increased endoplasmic reticulum and Golgi apparatus [1]. - Their **most important function is secretory** - they actively secrete cytokines (TNF-α, IL-1, IL-12), chemokines, and enzymes that maintain the granuloma structure and modulate the immune response [1]. - These secretory products help **contain the infection**, activate T-cells, and recruit other immune cells to form the organized granuloma [1]. - This secretory function is the defining characteristic that distinguishes them from ordinary macrophages. *Phagocytosis* - While epithelioid cells are derived from macrophages, their differentiation leads to **reduced phagocytic capacity**. - They have less prominent lysosomes and reduced ability to engulf pathogens compared to activated macrophages. - Their primary role has shifted from active phagocytosis to secretion and barrier formation. *Healing* - Epithelioid cells contribute to containment and eventual resolution of infection, but "healing" is not their direct primary function. - Healing involves fibrosis, collagen deposition (by fibroblasts), and tissue remodeling - processes distinct from the epithelioid cell's secretory role. - The granuloma itself (formed by epithelioid cells) may undergo **fibrosis or caseation**, but this is a consequence rather than the primary function. *Antigenic* - While epithelioid cells can present antigens (being derived from antigen-presenting macrophages), this is not their most important function in TB granulomas. - Antigen presentation is mainly carried out by dendritic cells and macrophages at earlier stages of immune response. - The defining role of epithelioid cells is their secretory activity that maintains granuloma structure. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 109.

Q: Caspase involved in activation of IL-1 is which of the following?

Caspase 1. ***Caspase 1*** - **Caspase 1** (also known as interleukin-1 beta converting enzyme or ICE) is the primary caspase responsible for the proteolytic cleavage and activation of pro-IL-1β and pro-IL-18 into their mature, active forms. - This activation occurs within the **inflammasome complex**, a multiprotein oligomer that assembles in response to various pathogens and danger signals. *Caspase 5* - While **Caspase 5** is an inflammatory caspase, similar to Caspase 1, it primarily functions in the direct activation of pro-IL-1β in certain contexts, particularly in response to *Gram-negative bacteria* through the non-canonical inflammasome. - However, **Caspase 1** is the canonical and most well-known activator of IL-1 in the classical inflammasome pathway. *Caspase 8* - **Caspase 8** is a key **initiator caspase** in the extrinsic pathway of apoptosis, activated by death receptors like Fas and TNF receptors. - Its primary role is in **apoptotic signaling** and it is not directly involved in the proteolytic activation of IL-1. *Caspase 3* - **Caspase 3** is a major **effector caspase** in both the intrinsic and extrinsic pathways of apoptosis. - It executes apoptosis by cleaving numerous cellular substrates and is not directly involved in the **processing of cytokines** like IL-1.

Q: Which of the following type of collagen is present in healing and granulation tissue?

Type III. ***Type III*** - **Type III collagen** is prominently found in **granulation tissue** during the early stages of wound healing [1]. - It provides a **scaffold** for cellular migration and proliferation [2], contributing to the initial strength of the healing tissue. *Type II* - **Type II collagen** is the primary collagen type found in **cartilage**, particularly **hyaline cartilage**. - It is crucial for the **structural integrity** and resilience of articular surfaces, not typically in granulation tissue. *Type I* - **Type I collagen** is the most abundant collagen in the body, providing **tensile strength** to tissues like bone, skin, tendons, and ligaments. - While ultimately replacing type III collagen in mature scar tissue, it is **less prevalent in initial granulation tissue** compared to type III [1]. *Type IV* - **Type IV collagen** is a major component of **basement membranes**, forming a mesh-like network [3]. - It provides **structural support** and acts as a selective filter in tissues such as the kidneys and lungs, but not in healing granulation tissue. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 105-106. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 32-34.

Q: Which feature is most consistent with chronic inflammation?

Fibrosis. ***Fibrosis*** - **Fibrosis** is the excessive accumulation of connective tissue, often seen as a **scarring process**, which is a hallmark of chronic inflammation as the body attempts to repair damaged tissue. [1] - Unlike acute inflammation, which is characterized by immediate vascular changes and exudation, chronic inflammation involves persistent tissue injury and attempts at repair, leading to **fibroblast proliferation** and collagen deposition. [2] *Hyperemia* - **Hyperemia** is an active process involving increased blood flow to a tissue, which causes it to redden. - It is a prominent feature of **acute inflammation**, contributing to rubor (redness) and calor (heat). *Vasodilation* - **Vasodilation**, the widening of blood vessels, is a key component of the **acute inflammatory response**. - It increases blood flow to the inflamed area, contributing to the cardinal signs of **redness and warmth**. *Edema* - **Edema** refers to the accumulation of excess fluid in the interstitial spaces, often due to increased vascular permeability. - While it can occur in both acute and chronic inflammation, it is a particularly prominent and early feature of **acute inflammation** as fluid rushes to the site of injury. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 103-104. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 194-195.

Q: Which of the following is/are characteristic features of chronic inflammation?

Tissue fibrosis and lymphocyte infiltration. ***Tissue fibrosis and lymphocyte infiltration*** - **Chronic inflammation** is characterized by the persistent presence of lymphocytes, plasma cells, and macrophages as the predominant inflammatory cells [1]. - **Tissue fibrosis** (scarring) and destruction are hallmarks of chronic inflammation as the body attempts to repair ongoing damage, often leading to loss of organ function [1]. *Infiltration of neutrophils* - **Neutrophils** are the primary inflammatory cells seen in **acute inflammation**, being the first responders to injury or infection [2]. - Their presence typically signifies an active, recent inflammatory process, usually resolving within hours to days. *Increased blood flow (hyperemia)* - **Hyperemia** is a classic sign of **acute inflammation**, contributing to the **redness and warmth** observed at the site. - While some vascular changes can persist in chronic inflammation, pronounced and primary hyperemia is characteristic of the acute phase. *Presence of fluid accumulation (edema) in tissues* - **Edema** primarily results from increased vascular permeability, a key feature of **acute inflammation**, causing swelling [2]. - While some edema may be present in chronic inflammation due to persistent vascular leakage, it is a dominant feature of acute inflammatory responses. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 109-110. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 103-104.

Q: A patient with chronic granulomatous disease is most likely to have a defect in which enzyme?

NADPH oxidase. ***NADPH oxidase*** - **Chronic granulomatous disease (CGD)** is characterized by a defect in **NADPH oxidase**, an enzyme critical for the formation of **superoxide radicals**. - Without a functional **NADPH oxidase**, phagocytes cannot mount a **respiratory burst** to kill certain bacteria and fungi, leading to recurrent infections and granuloma formation. *Superoxide dismutase* - This enzyme converts **superoxide** into **hydrogen peroxide** and oxygen, an essential step in detoxifying reactive oxygen species. - A defect here would lead to an accumulation of superoxide, but is not the primary cause of the susceptibility to specific infections seen in CGD. *Catalase* - **Catalase** breaks down **hydrogen peroxide** into water and oxygen, protecting cells from oxidative damage. - While important for reducing oxidative stress, its deficiency is not responsible for the impaired microbial killing in CGD, rather, it's involved in the *breakdown* of products generated by NADPH oxidase. *Myeloperoxidase* - **Myeloperoxidase (MPO)** combines **hydrogen peroxide** with chloride ions to produce **hypochlorous acid (bleach)**, a potent microbicidal agent. - Although crucial for killing, MPO can only function if NADPH oxidase first produces sufficient hydrogen peroxide; thus, its deficiency presents differently than CGD.

Question 1

The most important function of epithelioid cells in tuberculosis is -

Accepted Answer

Secretory

Answer

Phagocytosis

Answer

Healing

Answer

Antigenic

Question 2

Caspase involved in activation of IL-1 is which of the following?

Accepted Answer

Caspase 1

Answer

Caspase 5

Answer

Caspase 8

Answer

Caspase 3

Question 3

The following statement about keloid is true:

Accepted Answer

It will have more collagen and vascularity

Answer

Extended excision is the treatment of choice

Answer

Elevated levels of growth factor is not seen

Answer

They do not extend beyond the wound

Question 4

Which of the following type of collagen is present in healing and granulation tissue?

Accepted Answer

Type III

Answer

Type II

Answer

Type I

Answer

Type IV

Question 5

Which is NOT a feature of chronic inflammation?

Accepted Answer

Neutrophil predominance

Answer

Mononuclear cells

Answer

Fibrosis

Answer

Granulation tissue

Question 6

Which feature is most consistent with chronic inflammation?

Accepted Answer

Fibrosis

Answer

Hyperemia

Answer

Vasodilation

Answer

Edema

Question 7

Which of the following does not cause granulomatous inflammation?

Accepted Answer

Pneumonia

Answer

Sarcoidosis

Answer

Tuberculosis

Answer

Histoplasmosis

Question 8

Which of the following is/are characteristic features of chronic inflammation?

Accepted Answer

Tissue fibrosis and lymphocyte infiltration

Answer

Infiltration of neutrophils

Answer

Increased blood flow (hyperemia)

Answer

Presence of fluid accumulation (edema) in tissues

Question 9

A patient with chronic granulomatous disease is most likely to have a defect in which enzyme?

Accepted Answer

NADPH oxidase

Answer

Superoxide dismutase

Answer

Catalase

Answer

Myeloperoxidase

Question 10

A 30-year-old man with a history of Crohn's disease presents with abdominal pain and diarrhea. A biopsy reveals numerous non-caseating granulomas. What is the mechanism behind the formation of these granulomas?

Accepted Answer

Activated macrophages secrete TNF-alpha

Answer

Neutrophils release elastase and myeloperoxidase

Answer

B cells produce specific antibodies against self-antigens

Answer

CD8+ cytotoxic T cells are the primary mediators of granuloma formation

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

On this page

Practice by Chapter

Want unlimited practice?