Inflammation and Repair Practice Questions

Q: A patient presents with a wound on his leg. It heals six weeks later. Which of the following mediators is involved in promoting wound healing?

TGF-Beta. **Explanation:** **TGF-Beta (Transforming Growth Factor-Beta)** is the correct answer because it is the most critical cytokine involved in the **proliferative and remodeling phases** of wound healing. It acts as a potent fibrogenic agent by: 1. Stimulating the chemotaxis and proliferation of fibroblasts. 2. Increasing the synthesis of collagen and fibronectin while decreasing the degradation of the extracellular matrix (ECM) by inhibiting metalloproteinases. 3. Promoting angiogenesis and epithelialization. **Analysis of Incorrect Options:** * **TNF-Alpha (Tumor Necrosis Factor-Alpha):** This is a potent pro-inflammatory cytokine produced by macrophages. While it is involved in the initial inflammatory phase of wound healing, its chronic elevation actually impairs healing and is associated with chronic non-healing ulcers. * **IFN-Alpha & IFN-Beta (Type I Interferons):** These are primarily involved in innate antiviral immunity and the activation of MHC class I expression. They do not play a direct role in promoting collagen synthesis or tissue repair; in fact, interferons can sometimes inhibit fibroblast proliferation. **NEET-PG High-Yield Pearls:** * **TGF-Beta** is also known for its role in **limiting inflammation** (anti-inflammatory) and is a key mediator in the development of fibrosis in chronic organs (e.g., liver cirrhosis, pulmonary fibrosis). * **Platelet-Derived Growth Factor (PDGF)** is another high-yield mediator that works alongside TGF-Beta to trigger fibroblast migration and smooth muscle proliferation. * **Vitamin C and Zinc** are essential cofactors for collagen synthesis during the remodeling phase; deficiency leads to poor wound healing.

Q: Which of the following complement components is chemotactic?

C5a. The complement system is a crucial part of the innate immune response, involving a cascade of proteins that lead to pathogen clearance [1]. The correct answer is **C5a** because it is the most potent **chemoattractant** (chemotactic factor) of the complement system. * **C5a (Correct):** Known as a "complete" anaphylatoxin, C5a functions as a powerful chemotactic agent for neutrophils, monocytes, eosinophils, and basophils. It recruits these inflammatory cells to the site of infection and also increases vascular permeability. * **C3a (Incorrect):** While C3a is an **anaphylatoxin** (triggers histamine release from mast cells), it has negligible chemotactic activity compared to C5a. Its primary role is inducing local inflammation and vasodilation. * **C3b (Incorrect):** C3b acts primarily as an **opsonin**. It coats the surface of pathogens, making them "tasty" for phagocytes (macrophages and neutrophils) which possess C3b receptors. It also helps in the formation of C5 convertase. **High-Yield Clinical Pearls for NEET-PG:** 1. **Potency Order:** For chemotaxis, C5a is significantly more potent than C3a. 2. **Opsonization:** Remember the mnemonic **"C3b binds bacteria"** (Opsonization). 3. **Anaphylatoxins:** C3a, C4a, and C5a (in increasing order of potency: C4a < C3a < C5a). 4. **Membrane Attack Complex (MAC):** Formed by C5b-C9; essential for lysing Gram-negative bacteria like *Neisseria*. 5. **Deficiency:** C3 deficiency is the most severe as it is the central point of all three pathways, leading to recurrent pyogenic infections.

Question 1

A keloid scar is primarily composed of which type of tissue?

Accepted Answer

Dense collagen

Answer

Loose fibrous tissue

Answer

Granulomatous tissue

Answer

Loose areolar tissue

Question 2

Following surgery, the wound heals in a linear fashion without any complication. This type of healing is called?

Accepted Answer

Primary healing

Answer

Secondary healing

Answer

Delayed primary healing

Answer

Reepithelialization

Question 3

A 10-year-old male child complains of pain and swelling in the left foot after an injury while playing. What mediates the migration of leukocytes to the site of injury?

Accepted Answer

Chemokines

Answer

Cytokines

Answer

Histamine

Answer

Prostaglandins

Question 4

A patient presents with a wound on his leg. It heals six weeks later. Which of the following mediators is involved in promoting wound healing?

Accepted Answer

TGF-Beta

Answer

TNF-Alpha

Answer

INF-Beta

Answer

IFN-Alpha

Question 5

Which of the following hormones has the greatest effect on granulation tissue in wound healing?

Accepted Answer

Cortisol

Answer

Antidiuretic hormone (ADH)

Answer

Estrogen

Answer

Parathormone

Question 6

Which of the following is a preformed mediator of inflammation?

Accepted Answer

Serotonin

Answer

Prostaglandin

Answer

Dopamine

Answer

Leukotrienes

Question 7

A 54-year-old man presents with poor wound healing following laparoscopic hernia repair, despite small incision size. Further history reveals a diet deficient in vitamin C. Which extracellular matrix component's synthesis is most significantly affected by vitamin C deficiency?

Accepted Answer

Collagen

Answer

Elastin

Answer

Fibronectin

Answer

Integrin

Question 8

Which of the following is a sign of chronic inflammation?

Accepted Answer

Angiogenesis

Answer

Purulent exudate

Answer

Induration

Answer

Edema

Question 9

A 5-year-old boy punctures his thumb with a rusty nail. Four hours later, the thumb appears red and swollen. Which of the following serum proteins activates the complement, coagulation, and fibrinolytic systems at the site of injury?

Accepted Answer

Hageman factor

Answer

Bradykinin

Answer

Kallikrein

Answer

Plasmin

Question 10

Which of the following complement components is chemotactic?

Accepted Answer

C5a

Answer

C3a

Answer

Both

Answer

C3b

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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