General Pathology Practice Questions

Q: All of the following are intermediate filaments except?

Cadherin. **Explanation:** The cytoskeleton of a cell consists of three main components: microfilaments (actin), microtubules (tubulin), and **intermediate filaments (IFs)**. Intermediate filaments provide mechanical strength to cells and are categorized into several types based on their tissue distribution. **Why Cadherin is the correct answer:** **Cadherins** are not intermediate filaments; they are **transmembrane cell adhesion molecules**. They play a critical role in cell-cell junctions (like desmosomes and adherens junctions) by mediating calcium-dependent adhesion [1]. While cadherins often link to the cytoskeleton internally, they are structurally distinct from the IF family. **Analysis of incorrect options:** * **Lamin (Option A):** These are Type V intermediate filaments located within the nucleus (nuclear lamina). They provide structural support to the nuclear envelope and regulate DNA replication. * **Vimentin (Option C):** A Type III intermediate filament found in cells of **mesenchymal origin** (e.g., fibroblasts, endothelium, smooth muscle). It is a classic IHC marker for sarcomas. * **Desmin (Option D):** Also a Type III intermediate filament, specifically found in **all types of muscle cells** (skeletal, cardiac, and smooth). It is used as an IHC marker to identify myogenic tumors (e.g., rhabdomyosarcoma). **High-Yield Clinical Pearls for NEET-PG:** * **Cytokeratin:** IF for epithelial cells (Marker for Carcinomas). * **GFAP:** IF for glial cells (Marker for Astrocytomas). * **Neurofilaments:** IF for neurons (Marker for Neuroblastoma/Pheochromocytoma). * **Mallory Hyaline:** These are inclusions of pre-keratin intermediate filaments found in alcoholic liver disease. * **Diagnostic Tip:** If a question asks for a marker of "mesenchymal origin," always look for **Vimentin**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 23-24.

Q: Examine the above pedigree chart. Which one of the following diseases is the most likely for this situation?

Beta-thalassemia. ***Beta-thalassemia*** - Shows classic **autosomal recessive** inheritance pattern with **unaffected carrier parents** producing affected offspring, demonstrating **equal sex distribution** among affected individuals. - Consistent with the pedigree showing **affected children from consanguineous marriages** and **horizontal inheritance** pattern typical of recessive disorders. *Neurofibromatosis* - Follows **autosomal dominant** inheritance pattern where affected individuals would have at least **one affected parent** in each generation. - Would show **vertical transmission** through generations with approximately **50% risk** to offspring of affected individuals, which contradicts the pedigree pattern. *Colour blindness* - Demonstrates **X-linked recessive** inheritance with **male predominance** and affected males having **unaffected parents** but **carrier mothers**. - Would show characteristic pattern of **affected grandfathers** passing the trait through **carrier daughters** to affected grandsons, not the equal sex distribution seen. *Vitamin D resistant rickets* - Exhibits **X-linked dominant** inheritance where **affected males** pass the condition to **all daughters** but **no sons**. - Would demonstrate **no male-to-male transmission** and affected females having **50% risk** regardless of offspring sex, inconsistent with this pedigree.

Q: Obstructive shock is due to which of the following mechanisms?

Mechanical impediment to blood flow. Shock is defined as a state of cellular and tissue hypoxia due to reduced oxygen delivery or increased oxygen consumption [3]. **Obstructive shock** occurs when there is a **mechanical impediment to blood flow** into or out of the heart, despite normal myocardial function and adequate intravascular volume [1]. This obstruction leads to a drastic fall in cardiac output. **Why the other options are incorrect:** * **Cardiac pump failure (Option B):** This describes **Cardiogenic shock**, where the primary defect is the heart's inability to contract effectively (e.g., Myocardial Infarction) [3]. * **Peripheral pooling of blood (Option C):** This is the hallmark of **Distributive shock** (e.g., Sepsis, Anaphylaxis), characterized by massive vasodilation and decreased systemic vascular resistance [1]. * **Hypovolemia (Option D):** This defines **Hypovolemic shock**, caused by a loss of intravascular volume (e.g., Hemorrhage or dehydration). **High-Yield Clinical Pearls for NEET-PG:** 1. **Common Causes:** The "Big Three" causes of obstructive shock are **Tension Pneumothorax**, **Cardiac Tamponade**, and **Massive Pulmonary Embolism** [1], [2]. 2. **Hemodynamics:** Characterized by **decreased Cardiac Output (CO)** and **increased Systemic Vascular Resistance (SVR)** as a compensatory mechanism. 3. **Jugular Venous Pressure (JVP):** Unlike hypovolemic shock, JVP is typically **elevated** in obstructive shock (except in rare cases of SVC syndrome). 4. **Pulsus Paradoxus:** A classic finding in Cardiac Tamponade (an inspiratory drop in SBP >10 mmHg) [2]. 5. **Beck’s Triad:** (Hypotension, Muffled heart sounds, Distended neck veins) is specific for Cardiac Tamponade.

Q: Red infarction is typically seen in which organ?

Small intestine. **Explanation:** Infarction is classified into two types based on the amount of hemorrhage: **Red (Hemorrhagic)** and **White (Anemic)** [2]. **Why Small Intestine is Correct:** Red infarcts occur in tissues with a **dual blood supply**, loose textures, or where blood can collect in the infarcted zone [2]. The small intestine is a classic example because it has extensive collateral circulation (mesenteric arcades) [1]. When an arterial occlusion occurs, blood from collateral vessels seeps into the necrotic area. Additionally, red infarcts are characteristic of **venous occlusions** (e.g., mesenteric venous thrombosis) and **reperfusion injury**, both of which are common in the bowel [2]. **Analysis of Incorrect Options:** * **Kidney (A) & Heart (D):** These are solid organs with **end-arterial circulation**. When an artery is blocked, there is no secondary supply to bleed into the necrotic zone, resulting in a **White (Anemic) Infarct** [2]. * **Brain (B):** While the brain can undergo "hemorrhagic transformation," it typically undergoes **Liquefactive Necrosis**. In the context of primary arterial occlusion, it is generally considered a pale infarct unless reperfused. **High-Yield NEET-PG Pearls:** * **Mnemonic for Red Infarcts (S-L-O-B):** **S**pongiose tissue (Lung), **L**oose tissue (Testis/Ovary), **O**cclusion (Venous), **B**lood (Dual supply/Small Intestine/Liver). * **White Infarcts** occur in solid organs with a single blood supply: **Heart, Spleen, and Kidney** [2]. * **Morphology:** Red infarcts remain red/firm, while white infarcts are wedge-shaped with the apex pointing toward the occlusion [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 785-786. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, p. 140.

Question 1

All of the following are intermediate filaments except?

Accepted Answer

Cadherin

Answer

Lamin

Answer

Vimentin

Answer

Desmin

Question 2

Examine the above pedigree chart. Which one of the following diseases is the most likely for this situation?

Accepted Answer

Beta-thalassemia

Answer

Neurofibromatosis

Answer

Colour blindness

Answer

Vitamin D resistant rickets

Question 3

Which of the following is a proapoptotic marker?

Accepted Answer

BAX

Answer

BCL-X

Answer

BCL-2

Answer

Mcl-1

Question 4

Obstructive shock is due to which of the following mechanisms?

Accepted Answer

Mechanical impediment to blood flow

Answer

Cardiac pump failure

Answer

Peripheral pooling of blood

Answer

Hypovolemia

Question 5

What is the most reliable investigation for amyloid disease?

Accepted Answer

Rectal biopsy

Answer

Immunoglobulin assay

Answer

Ultrasound

Answer

Urine examination

Question 6

Fat necrosis is classically seen in which organ?

Accepted Answer

Breast

Answer

Heart

Answer

Brain

Answer

Lungs

Question 7

Red infarction is typically seen in which organ?

Accepted Answer

Small intestine

Answer

Kidney

Answer

Brain

Answer

Heart

Question 8

A 4-year-old boy presents with extremely pliable skin, easy bruising, and joint hyperextensibility. Biochemical studies show a deficiency of lysyl hydroxylase. What cellular or tissue component abnormalities would most likely be revealed by ultrastructural examination of a skin biopsy from this patient?

Accepted Answer

Collagen fibers

Answer

Actin-myosin filaments

Answer

Glycocalyx

Answer

Intermediate filaments

Question 9

Liquefactive necrosis on necrotic tissue results in which of the following?

Accepted Answer

Infarct

Answer

Gangrene

Answer

Embolism

Answer

Caseation

Question 10

Aspiration of fluid around the knee joint in a diabetic patient undergoing dialysis would show which of the following?

Accepted Answer

beta-2 microglobulin

Answer

AA amyloid

Answer

AL amyloid

Answer

Lactoferrin

General Pathology — MCQs

General Pathology — MCQs

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