General Pathology Practice Questions

Q: Oil red O staining is used for which type of specimen preparation?

Frozen section. **Explanation:** **Oil Red O** is a lysochrome (fat-soluble) dye used for the histological visualization of **lipids** (triglycerides and neutral fats) in tissue sections. **Why Frozen Section is Correct:** The fundamental principle of lipid staining is that the lipids must remain preserved within the tissue. In standard paraffin embedding, tissues undergo dehydration with **alcohol** and clearing with **xylene**. These organic solvents dissolve lipids, leaving behind empty vacuoles (as seen in adipocytes on H&E stains). To prevent this loss, the tissue must be processed using **frozen sections** (cryostat), which bypasses the use of lipid-dissolving organic solvents, thereby keeping the fat droplets intact for the dye to color. **Why Other Options are Incorrect:** * **B, C, & D:** Glutaraldehyde, Alcohol, and Formalin-fixed specimens are typically processed for paraffin embedding. Alcohol, in particular, is a potent lipid solvent. While formalin-fixed tissue can technically be used if cut on a freezing microtome, the standard "specimen preparation" required for successful Oil Red O staining in a clinical or exam context is the **frozen section**. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Application:** Oil Red O is used to diagnose **Fat Embolism Syndrome** (identifying fat globules in lung tissue or sputum) and to identify lipid-laden macrophages in **Atherosclerosis**. * **Other Lipid Stains:** Sudan Black B (stains myelin and phospholipids) and Osmium Tetroxide. * **Staining Result:** Lipids appear **bright red**, while nuclei (if counterstained with Hematoxylin) appear blue/black. * **Neuroanatomy Link:** It is used to demonstrate myelin breakdown products in Wallerian degeneration.

Q: Chemotherapeutic drugs can cause which of the following cellular death processes?

Both necrosis and apoptosis. The correct answer is **C. Both necrosis and apoptosis.** Chemotherapeutic agents are designed to eliminate rapidly dividing cancer cells, but they do so through diverse pathways depending on the drug concentration and the extent of cellular damage. 1. **Apoptosis (Programmed Cell Death):** Most chemotherapy drugs (e.g., Cisplatin, Etoposide) trigger intrinsic or extrinsic apoptotic pathways. When the drug causes manageable but lethal DNA damage or metabolic stress, the cell activates caspases, leading to an organized, energy-dependent shrinkage and fragmentation without an inflammatory response. Damaged DNA is typically detected and either repaired or triggers these pathways [1]. 2. **Necrosis (Accidental/Unprogrammed Death):** At high doses or when drugs cause severe, acute oxidative stress and massive ATP depletion, the cell cannot complete the energy-intensive apoptotic process. This leads to loss of membrane integrity, cellular swelling (oncosis), and rupture, resulting in an inflammatory response. **Why other options are incorrect:** * **Options A & B:** These are incorrect because cell death is a spectrum. A single drug can induce apoptosis at low concentrations and necrosis at high concentrations. * **Option D (Anoikis):** This is a specific subtype of apoptosis triggered by the loss of cell-to-matrix interaction. While some drugs may indirectly lead to this, it is not the primary mechanism for chemotherapy-induced death across all tissues. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Chemotherapy-induced apoptosis is primarily mediated by the **p53 protein**; mutations in p53 often lead to drug resistance. * **Morphology:** Apoptosis shows **chromatin condensation** and "apoptotic bodies," while necrosis shows **karyolysis** and membrane disruption. * **Biochemical Marker:** **Annexin V** staining is used to detect early apoptosis (it binds to phosphatidylserine flipped to the outer membrane).

Q: Caisson's disease is:

Gas embolism. **Explanation:** **Caisson’s disease**, also known as decompression sickness (DCS) or "the bends," occurs due to a rapid decrease in environmental pressure (e.g., a diver ascending too quickly). **Why Gas Embolism is Correct:** According to **Henry’s Law**, the solubility of a gas in a liquid is proportional to its partial pressure. At high pressures (deep underwater), large amounts of nitrogen dissolve into the blood and tissues. If decompression occurs rapidly, the nitrogen cannot stay dissolved and forms **bubbles** in the blood and tissues. These nitrogen bubbles act as **gas emboli**, obstructing blood flow and triggering inflammatory responses. **Analysis of Incorrect Options:** * **B. Fat Embolism:** Typically occurs after long bone fractures (e.g., femur) where fat globules from the bone marrow enter the circulation. * **C. Amniotic Fluid Embolism:** A rare obstetric emergency where amniotic fluid enters the maternal circulation during labor or delivery. * **D. Tumor Embolism:** Occurs when clusters of cancer cells break off from a primary tumor and enter the bloodstream, potentially leading to metastasis. **High-Yield Clinical Pearls for NEET-PG:** * **The Bends:** Joint and muscle pain caused by bubbles in local capillaries. * **The Chokes:** Shortness of breath and cough due to bubbles in pulmonary capillaries. * **Neurological symptoms:** Can include paralysis or sensory loss if bubbles form in the spinal cord. * **Treatment:** The definitive treatment is **Hyperbaric Oxygen Therapy (HBOT)**, which forces the nitrogen bubbles back into solution. * **Prevention:** Following decompression tables to allow for gradual "off-gassing."

Q: Which of the following is NOT a cell adhesion molecule?

Spectrin. **Explanation:** Cell adhesion molecules (CAMs) are transmembrane proteins located on the cell surface that facilitate cell-to-cell or cell-to-matrix interactions. They are essential for tissue integrity, leukocyte migration, and signal transduction. **Why Spectrin is the correct answer:** **Spectrin** is not a cell adhesion molecule; rather, it is a major **cytoskeletal protein**. It forms a hexagonal meshwork on the inner surface of the plasma membrane (especially in erythrocytes). Its primary role is to maintain cell shape, provide structural support, and allow for membrane flexibility. Mutations in spectrin lead to clinical conditions like **Hereditary Spherocytosis**. **Analysis of other options:** * **Integrins (Option A):** These are heterodimeric receptors that primarily mediate **cell-matrix** adhesion (e.g., binding to fibronectin or laminin). They also play a role in "inside-out" signaling. * **Selectins (Option B):** These are carbohydrate-binding proteins (L, E, and P-selectins) that mediate the initial **"rolling"** phase of leukocyte adhesion to vascular endothelium. * **Cadherins (Option C):** These are **calcium-dependent** homophilic adhesion molecules (e.g., E-cadherin) that are crucial for maintaining stable cell-to-cell junctions like desmosomes and adherens junctions. **High-Yield NEET-PG Pearls:** * **Calcium Dependency:** Cadherins and Selectins are calcium-dependent, whereas the Immunoglobulin (Ig) superfamily and Integrins are generally calcium-independent. * **Leukocyte Extravasation:** Remember the sequence: **Rolling** (Selectins) → **Activation** (Chemokines) → **Adhesion/Tethering** (Integrins/ICAM-1) → **Diapedesis** (PECAM-1). * **Clinical Link:** Loss of E-cadherin is a hallmark of **Epithelial-Mesenchymal Transition (EMT)** in cancer metastasis.

Question 1

Which of the following chromosomal abnormalities is NOT typically associated with Down syndrome?

Accepted Answer

Translocation t(11:14)

Answer

Translocation t(14:21)

Answer

Trisomy 21

Answer

Translocation t(15:21)

Question 2

Oil red O staining is used for which type of specimen preparation?

Accepted Answer

Frozen section

Answer

Glutaraldehyde fixed specimen

Answer

Alcohol fixed specimen

Answer

Formalin fixed specimen

Question 3

Chemotherapeutic drugs can cause which of the following cellular death processes?

Accepted Answer

Both necrosis and apoptosis

Answer

Only necrosis

Answer

Only apoptosis

Answer

Anoikis

Question 4

Caisson's disease is:

Accepted Answer

Gas embolism

Answer

Fat embolism

Answer

Amniotic fluid embolism

Answer

Tumor embolism

Question 5

A patient who previously had good muscle mass now presents with decreased muscle mass. There is a history of road traffic accident that led him to be bedridden for 6 months. This decrease in muscle mass is best explained by which of the following cellular adaptations?

Accepted Answer

Atrophy

Answer

Metaplasia

Answer

Dysplasia

Answer

Hypertrophy

Question 6

Which of the following is associated with Virchow's triad?

Accepted Answer

Hypercoagulability

Answer

Disseminated malignancy

Answer

Deep vein thrombosis (DVT)

Answer

All of the above

Question 7

Which of the following proteins is NOT typically found in amyloid deposits in senile amyloidosis?

Accepted Answer

AL protein

Answer

Transthyretin

Answer

Beta-amyloid protein

Answer

Amyloid of prion

Question 8

Endotoxic shock is propagated by which of the following mechanisms?

Accepted Answer

Cytokine action

Answer

Endothelial injury

Answer

Peripheral vasodilation

Answer

Increased vascular permeability

Question 9

Which of the following is NOT a cell adhesion molecule?

Accepted Answer

Spectrin

Answer

Integrin

Answer

Selectin

Answer

Cadherin

Question 10

What is the most common malignant neoplasm of infancy?

Accepted Answer

Neuroblastoma

Answer

Malignant teratoma

Answer

Wilms' tumor

Answer

Hepatoblastoma

General Pathology — MCQs

General Pathology — MCQs

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