General Pathology Practice Questions

Q: Which CD marker is expressed by NK cells?

CD 56. **Explanation:** Natural Killer (NK) cells are a subset of innate lymphoid cells that play a critical role in the host defense against viral infections and tumor surveillance [1]. **Why CD 56 is correct:** **CD 56** (Neural Cell Adhesion Molecule or NCAM) is the characteristic phenotypic marker used to identify **NK cells** in clinical practice and flow cytometry. Along with **CD 16** (an Fc receptor for IgG), CD 56 defines the NK cell population. NK cells are unique because they are "large granular lymphocytes" that lack the T-cell receptor (TCR) complex [1]. **Analysis of Incorrect Options:** * **CD 3:** This is the pan-T-cell marker [1]. It is part of the T-cell receptor (TCR) complex. Its absence is a key feature used to distinguish NK cells (CD3 negative) from NKT cells (CD3 positive). * **CD 19:** This is a primary marker for **B-cells** [1]. It is expressed from the early stages of B-cell development until the plasma cell stage. * **CD 13:** This is a **myeloid marker**, typically expressed on granulocytes, monocytes, and their precursors. It is frequently used in the diagnosis of Acute Myeloid Leukemia (AML). **High-Yield Clinical Pearls for NEET-PG:** * **NK Cell Markers:** CD 16, CD 56, and CD 94. * **Mechanism of Action:** NK cells kill target cells via **perforins and granzymes**, inducing apoptosis. * **Inhibitory Receptors:** NK cells express **KIR (Killer-cell Immunoglobulin-like Receptors)**, which recognize MHC Class I molecules on healthy cells to prevent "self-attack" [1]. * **Cytokine Activation:** NK cell activity is significantly enhanced by **IL-2 and IL-12** [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 200-201.

Q: What is the primary role of P-selectin in the process of inflammation?

Rolling of leukocytes along the vascular endothelium. ### Explanation The recruitment of leukocytes to the site of inflammation is a multi-step process known as the **Leukocyte Adhesion Cascade**. **1. Why Option A is Correct:** **P-selectin** (along with E-selectin) is responsible for the **Rolling** phase [1]. Selectins are carbohydrate-binding adhesion molecules. P-selectin is stored in the **Weibel-Palade bodies** of endothelial cells and is rapidly redistributed to the cell surface upon stimulation by mediators like histamine or thrombin. It binds to **Sialyl-Lewis X** ligands on leukocytes, creating weak, transient bonds that cause the cells to "roll" along the vessel wall, slowing them down for subsequent steps. **2. Why the Other Options are Incorrect:** * **Option B (Stable Adhesion):** This step is mediated by **Integrins** (e.g., LFA-1, VLA-4) on leukocytes binding to **ICAM-1** and **VCAM-1** on the endothelium [1]. * **Option C (Homing to Lymphoid Tissues):** This is primarily the role of **L-selectin**, which is expressed on leukocytes and facilitates their entry into high endothelial venules (HEVs) of lymph nodes [1]. * **Option D (Transmigration/Diapedesis):** The movement across the endothelium is mediated by **PECAM-1 (CD31)**, located at the intercellular junctions of endothelial cells. **High-Yield NEET-PG Pearls:** * **Storage:** P-selectin is stored in **Weibel-Palade bodies** (which also store von Willebrand factor). * **Deficiency:** A defect in the synthesis of Sialyl-Lewis X (the ligand for selectins) leads to **Leukocyte Adhesion Deficiency (LAD) Type 2**, characterized by recurrent infections and a lack of pus formation. * **Sequence:** Rolling (Selectins) [1] → Activation (Chemokines) → Adhesion (Integrins) [1] → Transmigration (PECAM-1). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 87.

Question 1

Calcification in necrotic tissue is called?

Accepted Answer

Dystrophic calcification

Answer

Metastatic calcification

Answer

Calcinosis

Answer

Tumoral calcinosis

Question 2

At what time frame does reversible injury in the myocardium typically occur?

Accepted Answer

30 minutes

Answer

2 minutes

Answer

2 hours

Answer

5 hours

Question 3

Most commonly, paraneoplastic syndromes are associated with which type of carcinoma?

Accepted Answer

Small cell carcinoma

Answer

Bronchial carcinoid

Answer

Broncho-alveolar carcinoma

Answer

Bronchial adenocarcinoma

Question 4

From which source are stem cells typically harvested?

Accepted Answer

Bone marrow

Answer

Skin

Answer

Oral mucosa

Answer

Elementary tract

Question 5

Increased functional demand on the heart produces an increased size of the myocardium by which of the following mechanisms?

Accepted Answer

Hypertrophy

Answer

Hyperplasia

Answer

Calcification

Answer

Fatty infiltration

Question 6

Marfan syndrome is due to a mutation of which of the following proteins?

Accepted Answer

Fibrillin

Answer

Collagen

Answer

Elastin

Answer

Fibronectin

Question 7

Which CD marker is expressed by NK cells?

Accepted Answer

CD 56

Answer

CD 3

Answer

CD 19

Answer

CD 13

Question 8

What is the primary role of P-selectin in the process of inflammation?

Accepted Answer

Rolling of leukocytes along the vascular endothelium

Answer

Stable adhesion of leukocytes to the vascular endothelium

Answer

Directing leukocytes to specific lymphoid tissues

Answer

Movement of leukocytes across the vascular endothelium

Question 9

Which of the following conditions is characterized by epithelioid granulomas?

Accepted Answer

Sarcoidosis

Answer

Eosinophilia

Answer

Tuberculosis

Answer

Mycosis Fungoides

Question 10

Which of the following are stable cells?

Accepted Answer

Mesenchymal cells

Answer

The lining mucosa of the glands

Answer

Nerve cells

Answer

Stratified squamous epithelium of the oral cavity

General Pathology — MCQs

General Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?