General Pathology Practice Questions

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

Caisson's disease is:

Accepted Answer

Gas embolism

Answer

Fat embolism

Answer

Amniotic fluid embolism

Answer

Tumor embolism

Question 2

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 3

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 4

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 5

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 6

Which of the following is NOT a cell adhesion molecule?

Accepted Answer

Spectrin

Answer

Integrin

Answer

Selectin

Answer

Cadherin

Question 7

What is the most common malignant neoplasm of infancy?

Accepted Answer

Neuroblastoma

Answer

Malignant teratoma

Answer

Wilms' tumor

Answer

Hepatoblastoma

Question 8

Fibrinoid necrosis can be seen in:

Accepted Answer

Peptic ulcer.

Answer

Abscess cavity.

Answer

Pancreas.

Answer

Heart.

Question 9

A one-year-old boy presented with hepatosplenomegaly and delayed milestones. Liver biopsy and bone marrow biopsy revealed histiocytes with PAS-positive, diastase-resistant material in the cytoplasm. Electron-microscopic examination of these histiocytes is most likely to reveal the presence of?

Accepted Answer

Parallel arrays of tubular structures in lysosomes

Answer

Birbeck's granules in the cytoplasm

Answer

Myelin figures in the cytoplasm

Answer

Electron-dense deposits in the mitochondria

Question 10

Amplification of N-myc is associated with which tumour?

Accepted Answer

Neuroblastoma

Answer

Retinoblastoma

Answer

Osteosarcoma

Answer

Neuroma

General Pathology — MCQs

General Pathology — MCQs

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