General Pathology Practice Questions

Q: Factor V Leiden is resistant to direct inactivation by:

Activated protein C. **Explanation:** **Factor V Leiden** is the most common inherited cause of hypercoagulability (thrombophilia). It results from a specific point mutation (G1691A) in the Factor V gene, where the amino acid **Arginine is replaced by Glutamine at position 506**. **Why Activated Protein C (APC) is the correct answer:** In the normal anticoagulation pathway, **Activated Protein C (APC)** inactivates procoagulant factors Va and VIIIa by cleaving them at specific sites. The mutation in Factor V Leiden alters the cleavage site (Arg506) where APC normally binds. Consequently, Factor V remains in its active form for longer, leading to a state of "APC Resistance" and an increased risk of venous thromboembolism (VTE). **Analysis of Incorrect Options:** * **A. Thrombin-thrombomodulin complex:** This complex is responsible for *activating* Protein C into APC. It does not directly inactivate Factor V; rather, it initiates the pathway that leads to its inactivation. * **B. Antithrombin:** Antithrombin primarily inhibits Thrombin (IIa) and Factor Xa. While it is a major natural anticoagulant, its primary target is not Factor V. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Autosomal Dominant. * **Clinical Presentation:** Recurrent Deep Vein Thrombosis (DVT) and Pulmonary Embolism. * **Diagnosis:** Suspected when a patient has a shortened Activated Partial Thromboplastin Time (aPTT) that does not prolong significantly upon the addition of APC (APC Resistance Test). * **Genetic Confirmation:** PCR is the gold standard to identify the G1691A mutation. * **Risk:** Heterozygotes have a 5-10 fold increased risk of VTE; homozygotes have up to an 80-fold increased risk.

Q: Which of the following statements regarding coagulative necrosis is false?

Affected tissue has a cheese-like appearance.. **Explanation:** **Why Option D is the correct answer (False statement):** A "cheese-like" (friable, yellow-white) appearance is the hallmark of **Caseous necrosis**, not coagulative necrosis [1]. Caseous necrosis is typically seen in granulomatous inflammation, most notably in Tuberculosis [1]. In contrast, coagulative necrosis results in firm, opaque, and pale tissue. **Analysis of other options:** * **Option A (Most common type):** This is a true statement. Coagulative necrosis is the most frequent pattern of cell death encountered in clinical practice. * **Option B (Ischemia):** This is true. Ischemia (loss of blood supply) is the primary cause of coagulative necrosis in all solid organs except the brain (where ischemia leads to liquefactive necrosis). * **Option C (Tombstone appearance):** This is a classic histological description. In coagulative necrosis, the cell's structural framework is preserved for several days despite the loss of the nucleus. The cells appear as "ghostly" outlines or "tombstones" because the denaturation of proteins prevents immediate proteolysis. **NEET-PG High-Yield Pearls:** 1. **Mechanism:** The primary mechanism is the **denaturation of structural proteins and enzymes**, which blocks proteolysis (autolysis). 2. **Microscopy:** Characterized by increased eosinophilia (due to loss of cytoplasmic RNA) and nuclear changes (pyknosis → karyorrhexis → karyolysis). 3. **Exception Rule:** Ischemia in the **Brain** leads to **Liquefactive necrosis**, not coagulative. 4. **Clinical Example:** Myocardial Infarction (MI) is the most common clinical example of coagulative necrosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, p. 55.

Question 1

Oncocytes are a modified form of which organelle?

Accepted Answer

Mitochondria

Answer

Nucleolus

Answer

Endoplasmic Reticulum

Answer

Lysosomes

Question 2

Factor V Leiden is resistant to direct inactivation by:

Accepted Answer

Activated protein C

Answer

Thrombin-thrombomodulin complex

Answer

Antithrombin

Answer

All of the above

Question 3

Coagulation defect involving both the arterial and venous system is seen in which of the following conditions?

Accepted Answer

Hyperhomocystinemia

Answer

Factor V Leiden

Answer

Protein C deficiency

Answer

Antithrombin III deficiency

Question 4

All the following organs are likely to undergo coagulative necrosis except?

Accepted Answer

Brain

Answer

Spleen

Answer

Heart

Answer

Kidney

Question 5

Fibrinoid necrosis is typically seen in which of the following conditions?

Accepted Answer

Sarcoidosis

Answer

Polyarteritis nodosa

Answer

Systemic lupus erythematosus

Answer

Human immunodeficiency virus infection

Question 6

Which of the following statements regarding coagulative necrosis is false?

Accepted Answer

Affected tissue has a cheese-like appearance.

Answer

It is the most common type of necrosis.

Answer

Ischemia can lead to coagulative necrosis.

Answer

Affected tissue appears as a 'tombstone'.

Question 7

All of the following processes show features of acute inflammation except?

Accepted Answer

Apoptosis

Answer

Pyroptosis

Answer

Necroptosis

Answer

Necrosis

Question 8

Generation of free radicals occurs by all of the following mechanisms EXCEPT?

Accepted Answer

Reperfusion after ischemic injury

Answer

Normal metabolism

Answer

Oxygen toxicity

Answer

All of the above

Question 9

What is the most important change that occurs in irreversible cell injury?

Accepted Answer

Membrane damage

Answer

Decreased basophilia

Answer

Pyknosis

Answer

Accumulation of myelin figures

Question 10

What change is typically observed in mitochondria due to aging?

Accepted Answer

Decrease in both size and number

Answer

Decrease in size and increase in number

Answer

Decrease in number and increase in size

Answer

Increase in both size and number

General Pathology — MCQs

General Pathology — MCQs

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