General Pathology Practice Questions

Q: Malarial pigment is formed by?

Hemoglobin. **Explanation:** The correct answer is **Hemoglobin**. **Why Hemoglobin is correct:** Malarial pigment, also known as **hemozoin**, is a dark brown, granular byproduct of the digestion of host erythrocytes by *Plasmodium* parasites. Within the red blood cell, the parasite consumes host **hemoglobin** to obtain essential amino acids. However, this process releases free **heme**, which is toxic to the parasite. To detoxify it, the parasite polymerizes the reactive heme into an insoluble, non-toxic crystalline form called hemozoin. This pigment is a hallmark of malarial infection and is visible under light microscopy within the parasite's food vacuole. **Why other options are incorrect:** * **Parasite:** While the parasite *creates* the pigment, the pigment itself is chemically derived from the host's hemoglobin, not the parasite's own cellular structures. * **Bilirubin:** Bilirubin is a breakdown product of heme metabolism in the human liver/spleen. While malaria causes hemolysis leading to indirect hyperbilirubinemia (jaundice), it is not the constituent of the malarial pigment found inside the RBC. **High-Yield Clinical Pearls for NEET-PG:** * **Schüffner’s dots:** These are different from malarial pigment; they are morphological changes (stippling) in the RBC membrane seen specifically in *P. vivax* and *P. ovale*. * **Detection:** Hemozoin is birefringent under polarized light. * **Drug Mechanism:** Chloroquine works by inhibiting the biocrystallization of heme into hemozoin, leading to a buildup of toxic heme that kills the parasite. * **Phagocytosis:** After the RBC ruptures, malarial pigment is taken up by monocytes and macrophages (reticuloendothelial system), often leading to a slate-grey discoloration of the spleen and liver in chronic cases.

Q: Pale infarct is seen in all of the following organs except?

Lungs. Infarcts are classified into two types based on their color and the nature of the blood supply to the organ: **Pale (White) Infarcts** and **Red (Hemorrhagic) Infarcts.** **Why Lungs (Option A) is the correct answer:** The lungs are the classic site for **Red Infarcts**. This occurs because the lungs have a **dual blood supply** (Pulmonary and Bronchial arteries) [1] and a loose, spongy tissue architecture. When an obstruction occurs, blood from the collateral circulation seeps into the necrotic area, causing a hemorrhagic appearance. Red infarcts also typically occur in tissues with venous occlusion or previously congested tissues. **Why the other options are incorrect:** * **Spleen (Option B), Kidney (Option C), and Heart (Option D):** These are solid organs with **end-arterial circulation** (minimal collateral supply). When the primary artery is occluded, there is no secondary source of blood to fill the area, resulting in a "pale" or "white" appearance due to coagulative necrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Pale Infarcts (White):** Occur in solid organs with single-artery supply (Heart, Spleen, Kidney). * **Red Infarcts (Hemorrhagic):** Occur in organs with dual blood supply (Lungs, Liver, Small Intestine), loose tissues, or following reperfusion (e.g., after angioplasty). * **Morphology:** Most infarcts are **wedge-shaped**, with the apex pointing toward the site of vascular occlusion and the base toward the organ periphery. * **Exception:** The Brain is a solid organ, but it undergoes **liquefactive necrosis** rather than coagulative necrosis [2].

Q: What is the pattern of inheritance shown in the given pedigree chart?

Holandric inheritance. ***Holandric inheritance*** - Only **males are affected** across all generations, with **all sons of affected fathers** being affected, indicating **Y-linked inheritance**. - **No females** are ever affected since they do not inherit the **Y chromosome**, which is the hallmark of holandric inheritance. *X-linked dominant* - Would show **affected females** transmitting the trait to **both sons and daughters**, which is not seen here. - **Affected males** would have **all affected daughters** but **no affected sons**, contrary to the pedigree pattern. *Autosomal dominant* - Would affect **both males and females** equally, with **50% of offspring** from affected parents being affected. - **Vertical transmission** would occur through **both sexes**, not exclusively through males as shown. *X-linked recessive* - Would primarily affect **males** but show **carrier females** who can transmit to affected **grandsons through unaffected daughters**. - **Affected males** would have **unaffected sons** and **carrier daughters**, not all affected sons as seen here.

Question 1

Petechiae in scurvy is due to which of the following?

Accepted Answer

Endothelial disintegration

Answer

Platelet dysfunction

Answer

Thrombocytopenia

Answer

Clotting factor deficiency

Question 2

Malarial pigment is formed by?

Accepted Answer

Hemoglobin

Answer

Parasite

Answer

Bilirubin

Answer

Any of the above

Question 3

Which of the following statements regarding lipofuscin is not true?

Accepted Answer

It results in excessive lipid accumulation in the circulation

Answer

Perinuclear location

Answer

It is yellow-brown in color

Answer

Has a role in lipid peroxidation

Question 4

Conversion of normal cell into their tombstones is the hallmark of which type of necrosis?

Accepted Answer

Coagulative necrosis.

Answer

Liquefaction necrosis.

Answer

Caseous necrosis.

Answer

Gangrenous necrosis.

Question 5

Which of the following cell types is least sensitive to anoxia?

Accepted Answer

Fibroblasts

Answer

Neurons

Answer

Cardiac myocytes

Answer

Proximal renal tubule cells

Question 6

Pale infarct is seen in all of the following organs except?

Accepted Answer

Lungs

Answer

Spleen

Answer

Kidney

Answer

Heart

Question 7

What is the pattern of inheritance shown in the given pedigree chart?

Accepted Answer

Holandric inheritance

Answer

X-linked dominant

Answer

Autosomal dominant

Answer

X-linked recessive

Question 8

Which of the following acquired conditions is low risk for thrombosis?

Accepted Answer

Oral contraceptive use

Answer

Heparin-induced thrombocytopenia

Answer

Antiphospholipid antibody syndrome

Answer

Myocardial infarction

Question 9

Apoptosis causes all of the following except:

Accepted Answer

Local inflammatory response

Answer

Activation of caspase

Answer

Condensation of chromatin

Answer

Cleavage of chromatin by endonucleases

Question 10

Which protein is implicated in Familial Amyloidosis?

Accepted Answer

Transthyretin

Answer

Serum amyloid A

Answer

b2-microglobulin

Answer

Amyloid b peptide

General Pathology — MCQs

General Pathology — MCQs

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