General Pathology Practice Questions

Q: Which of the following is NOT a feature of Marfan's syndrome?

Reduced joint mobility. Explanation: Marfan’s syndrome is an **autosomal dominant** connective tissue disorder caused by a mutation in the **FBN1 gene** on chromosome 15, which encodes **Fibrillin-1** [1]. Fibrillin-1 is essential for the structural integrity of the extracellular matrix and for regulating TGF-β signaling [1]. 1. **Why "Reduced joint mobility" is correct:** Patients with Marfan’s syndrome typically exhibit **joint hypermobility** (laxity) rather than reduced mobility [1]. This occurs because the defective fibrillin leads to weakened ligaments and connective tissue. In contrast, reduced joint mobility (contractures) is a hallmark of *Congenital Contractural Arachnodactyly* (Beals Syndrome), caused by FBN2 mutations. 2. **Analysis of incorrect options:** * **Arachnodactyly:** This refers to "spider-like," abnormally long and slender fingers. It is a classic skeletal feature of Marfan’s, often assessed via the Steinberg (thumb) and Walker-Murdoch (wrist) signs [1]. * **Dislocation of the lens (Ectopia lentis):** This occurs in ~60% of patients. Characteristically, the dislocation is **upward and outward** (superior-temporal) due to weakness in the ciliary zonules. * **Aortic dissection:** This is the most serious complication. Cystic medial necrosis leads to dilation of the aortic root, predisposed to Type A dissection and aortic regurgitation [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of death:** Aortic dissection/rupture [1]. * **Cardiovascular:** Mitral Valve Prolapse (MVP) is also frequently seen [1]. * **Differentiation:** To distinguish from Homocystinuria (which also has Marfanoid habitus), remember that Homocystinuria has **downward** lens dislocation, intellectual disability, and increased risk of thrombosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 153-154.

Q: Edema is caused by all of the following mechanisms, EXCEPT?

Increased plasma proteins. This question tests your understanding of **Starling’s Forces**, which govern fluid movement between the intravascular and interstitial compartments. Edema occurs when there is an imbalance in these forces, leading to excess fluid accumulation in the tissues. ### **Explanation of the Correct Answer** **D. Increased plasma proteins:** This is the correct answer because increased plasma proteins (specifically albumin) would **increase plasma oncotic pressure**. According to Starling’s law, plasma oncotic pressure acts as a "magnet" that pulls fluid from the interstitium back into the capillaries. Therefore, an increase in plasma proteins would actually **prevent** edema. Conversely, *decreased* plasma proteins (hypoalbuminemia), seen in Nephrotic syndrome or liver cirrhosis, is a classic cause of edema. ### **Analysis of Incorrect Options** * **A. Increased vascular permeability:** Inflammation or toxins cause endothelial gaps, allowing fluid and proteins to leak into the interstitium (Exudate). This is a hallmark of acute inflammation. * **B. Obstruction to lymphatic flow:** Lymphatics normally drain the small amount of fluid that escapes capillaries. Obstruction (e.g., Filariasis, post-mastectomy) leads to **Lymphedema**. * **C. Sodium retention:** Excess sodium leads to water retention, increasing the **capillary hydrostatic pressure**, which pushes fluid into the tissues. This is seen in Heart Failure and Renal Failure. ### **High-Yield Clinical Pearls for NEET-PG** * **Starling’s Equation:** $Net\ Fluid\ Movement = K_f [(P_c - P_i) - \sigma(\pi_c - \pi_i)]$. * **Pitting Edema:** Usually caused by low oncotic pressure or high hydrostatic pressure (e.g., Cardiac failure). * **Non-pitting Edema:** Characteristic of **Lymphedema** and **Myxedema** (Hypothyroidism due to deposition of mucopolysaccharides). * **First sign of Edema:** Weight gain usually precedes visible clinical edema.

Q: What is the important function of cytosolic cytochrome C?

Apoptosis. ### Explanation **Correct Answer: A. Apoptosis** Cytochrome C is a peripheral membrane protein typically located in the inner mitochondrial membrane. Its presence in the **cytosol** is a hallmark of the **intrinsic (mitochondrial) pathway of apoptosis**. When a cell undergoes stress (DNA damage, oxidative stress, or withdrawal of growth factors), the pro-apoptotic proteins **BAX and BAK** create pores in the mitochondrial outer membrane. This leads to the leakage of Cytochrome C into the cytosol. Once in the cytosol, Cytochrome C binds to **Apaf-1** (Apoptotic protease activating factor-1) and ATP to form a wheel-like complex called the **Apoptosome**. This complex activates **Caspase-9**, triggering a proteolytic cascade that leads to programmed cell death. **Why other options are incorrect:** * **B. Cell Necrosis:** Necrosis is an uncontrolled, accidental cell death characterized by cell swelling and membrane rupture. It is not mediated by the specific Cytochrome C/Caspase pathway. * **C. Electron Transport Chain (ETC):** While Cytochrome C is vital for the ETC (shuttling electrons between Complex III and IV), this function occurs strictly **within the mitochondria**, not the cytosol. The question specifically asks for the *cytosolic* function. * **D. Cell Division:** Cytochrome C has no direct regulatory role in mitosis or the cell cycle. **High-Yield Clinical Pearls for NEET-PG:** * **The "Point of No Return":** The release of Cytochrome C into the cytosol is considered the irreversible step in the intrinsic pathway of apoptosis. * **Bcl-2 Family:** Remember that **Bcl-2 and Bcl-xL** are anti-apoptotic (they prevent Cytochrome C release), while **BAX and BAK** are pro-apoptotic. * **Caspase Cascade:** Intrinsic pathway = Caspase **9**; Extrinsic (Death Receptor) pathway = Caspase **8**. Both converge on executioner Caspases **3 and 6**.

Question 1

A one-year-old boy presented with hepatosplenomegaly and delayed milestones. Liver biopsy and bone marrow biopsy revealed the presence of 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 granules in the cytoplasm

Answer

Myelin figures in the cytoplasm

Answer

Electron-dense deposits in the mitochondria

Question 2

A 10-year-old male, who is mentally retarded, can perform daily living activities, including feeding and dressing himself. Physical examination reveals brachycephaly, oblique palpebral fissures with prominent epicanthal folds, and a single transverse palmar crease. Auscultation of the chest reveals a grade III/IV systolic murmur. Which of the following conditions is most likely to be present by the age of 20?

Accepted Answer

Acute leukemia

Answer

Hepatic cirrhosis

Answer

Chronic renal failure

Answer

Acute myocardial infarction

Question 3

Lipofuscin-containing macrophages are a characteristic feature of which process?

Accepted Answer

Wear and tear

Answer

Fat deposit

Answer

Iron deficiency

Answer

Calcification

Question 4

Which of the following is NOT a feature of Marfan's syndrome?

Accepted Answer

Reduced joint mobility

Answer

Arachnodactyly

Answer

Dislocation of the lens

Answer

Aortic dissection

Question 5

Aging is most probably due to:

Accepted Answer

Accumulated free radical injury in tissues

Answer

Non-random mutation in somatic cells

Answer

Decrease in collagen cross-linking

Answer

Increase in superoxide dismutase

Question 6

Edema is caused by all of the following mechanisms, EXCEPT?

Accepted Answer

Increased plasma proteins

Answer

Increased vascular permeability

Answer

Obstruction to lymphatic flow

Answer

Sodium retention

Question 7

SMAC/DIABLO is a:

Accepted Answer

Pro-apoptotic protein

Answer

Anti-apoptotic protein

Answer

Induces necrosis

Answer

Acts both as anti- and pro-apoptotic protein

Question 8

Cystic fibrosis is inherited as an autosomal recessive condition. A normal couple has one daughter affected with the disease. They are now planning to have another child. What is the chance of her sibling being affected by the disease?

Accepted Answer

1/4

Answer

0

Answer

1/2

Answer

3/4

Question 9

A 28-year-old female presents with recurrent abortions and pain in the calves. She is most likely suffering from a deficiency of which of the following?

Accepted Answer

Protein C

Answer

Thrombin

Answer

Factor XIII

Answer

Plasmin

Question 10

What is the important function of cytosolic cytochrome C?

Accepted Answer

Apoptosis

Answer

Cell necrosis

Answer

Electron transport chain

Answer

Cell division

General Pathology — MCQs

General Pathology — MCQs

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