General Pathology Practice Questions

Q: The embolus depicted in the cross-section is an example of which type?

Saddle embolus. ***Saddle embolus*** - An embolus that **straddles a vessel bifurcation** in cross-section, resembling a saddle across the branching point. - Most commonly occurs at the **pulmonary artery bifurcation** (pulmonary saddle embolus) or **aortic bifurcation**, causing bilateral obstruction and severe hemodynamic compromise. *Paradoxical embolus* - Occurs when an embolus crosses from the **venous to arterial circulation** through a **right-to-left shunt** (e.g., patent foramen ovale). - Does not describe the **morphological appearance** of an embolus straddling a bifurcation as seen in cross-section. *Retrograde embolus* - An embolus that travels **against the normal direction of blood flow**, typically due to reversal of flow or gravitational effects. - This term describes the **direction of movement**, not the characteristic cross-sectional appearance at a vessel bifurcation. *Atheroembolus* - Composed of **cholesterol crystals** and **atherosclerotic plaque material** that breaks off from ulcerated plaques. - Typically appears as **needle-shaped cholesterol clefts** in tissue sections, not as a large embolus straddling a bifurcation.

Q: Hemorrhagic infarction is seen in which of the following conditions?

Venous thrombosis. **Explanation:** The correct answer is **Venous Thrombosis**. **1. Why Venous Thrombosis is correct:** In the brain, venous drainage is responsible for removing deoxygenated blood. When a cerebral venous sinus or vein is occluded (e.g., Superior Sagittal Sinus thrombosis), the inflow of arterial blood continues, but the outflow is blocked. This leads to a rapid increase in retrograde capillary hydrostatic pressure, causing the rupture of small vessels and the leakage of blood into the infarcted tissue. This process transforms an ischemic area into a **hemorrhagic infarction** [1]. **2. Why other options are incorrect:** * **Thrombosis (Arterial):** Arterial thrombosis typically causes a "pale" or "white" infarct because the blood supply is cut off at the source, preventing blood from entering the distal tissue [1]. * **Septicaemia:** While septicaemia can cause disseminated intravascular coagulation (DIC) or petechial hemorrhages, it is not a primary cause of localized hemorrhagic infarction. * **Embolism:** While embolic strokes *can* undergo secondary hemorrhagic transformation (reperfusion injury), the classic association for a primary, inherently hemorrhagic infarct in neuroanatomy exams is venous occlusion [1]. **3. NEET-PG High-Yield Pearls:** * **Venous Infarcts** are often bilateral and do not follow traditional arterial territories. * **Common Site:** Superior Sagittal Sinus is the most common site for venous thrombosis, often associated with pregnancy, dehydration, or hypercoagulable states. * **Imaging:** On MRI/CT, look for the **"Empty Delta Sign"** (post-contrast) in the superior sagittal sinus. * **Rule of Thumb:** Arterial occlusion = Pale Infarct; Venous occlusion = Hemorrhagic Infarct [1].

Q: The given pedigree chart most appropriately resembles which of the following diseases?

Duchenne's muscular dystrophy. ***Duchenne's muscular dystrophy*** - Exhibits classic **X-linked recessive inheritance** pattern with affected males, unaffected carrier females, and **no male-to-male transmission**. - The **dystrophin gene** mutation on the X chromosome causes progressive muscle weakness primarily in boys, matching the pedigree pattern. *Rett syndrome* - Follows **X-linked dominant inheritance** with affected females and is typically **lethal in males**. - Shows a different pattern where affected mothers can pass the condition to both male and female offspring. *Albinism* - Demonstrates **autosomal recessive inheritance** affecting both males and females equally when both parents are carriers. - Would show horizontal pattern in siblings rather than the **vertical male-predominant** pattern seen in X-linked conditions. *Marfan syndrome* - Follows **autosomal dominant inheritance** with **vertical transmission** through generations affecting both sexes equally. - Shows **50% risk** to offspring regardless of gender, unlike the sex-linked pattern in the pedigree.

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).

Question 1

Hemorrhagic infarction is seen in all except:

Accepted Answer

Septicemia

Answer

Venous thrombosis

Answer

Thrombosis

Answer

Embolism

Question 2

The embolus depicted in the cross-section is an example of which type?

Accepted Answer

Saddle embolus

Answer

Paradoxical embolus

Answer

Retrograde embolus

Answer

Atheroembolus

Question 3

Which of the following is NOT a mononuclear-macrophage?

Accepted Answer

B-cells

Answer

Histiocytes

Answer

Microglia

Answer

Kupffer cells

Question 4

Hemorrhagic infarction is seen in which of the following conditions?

Accepted Answer

Venous thrombosis

Answer

Thrombosis

Answer

Septicaemia

Answer

Embolism

Question 5

A 60-year-old man presents with acute liver failure and undergoes successful orthotopic liver transplantation. For the first 3 days post-transplant, the graft exhibits poor function, characterized by minimal bile production. This poor graft function is attributed to reperfusion injury. Which of the following substances is the most likely cause of reperfusion injury in this transplanted liver?

Accepted Answer

Reactive oxygen species

Answer

Cationic proteins

Answer

Free ferric iron

Answer

Hydrochlorous acid

Question 6

All of the following are stress sensors/regulators for apoptosis, except?

Accepted Answer

BAX

Answer

Puma

Answer

Noxa

Answer

BiM

Question 7

The given pedigree chart most appropriately resembles which of the following diseases?

Accepted Answer

Duchenne's muscular dystrophy

Answer

Rett syndrome

Answer

Albinism

Answer

Marfan syndrome

Question 8

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 9

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 10

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

General Pathology — MCQs

General Pathology — MCQs

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