50 Year 3: Endocrine and Metabolic Pathology exam questions on 50 Multiple Choice Questions for medical students. Includes MCQs, answers, explanations and writt
This MCQ set contains 50 questions on 50 Multiple Choice Questions in the Year 3: Endocrine and Metabolic Pathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.
Correct answer: A – Enlargement of skeletal muscle in bodybuilders
Physiologic hypertrophy occurs in response to normal stimuli like exercise or hormonal stimulation during pregnancy. Skeletal muscle enlargement with exercise is a classic example. Option B represents pathologic hypertrophy due to increased workload from disease.
Correct answer: B – Metaplasia
Barrett esophagus represents metaplasia where normal stratified squamous epithelium is replaced by columnar epithelium with goblet cells in response to chronic acid reflux. This is an adaptive response to chronic injury.
Correct answer: D – All of the above
All three are potentially reversible if the causative stimulus is removed before irreversible damage occurs. However, dysplasia has a higher risk of progression to cancer if the stimulus persists. ---
Correct answer: A – Excessive estrogen stimulation
Endometrial hyperplasia results from unopposed estrogen stimulation without adequate progesterone. This leads to increased proliferation of endometrial glands and can be a precursor to endometrial carcinoma. ---
Correct answer: C – Increased autophagy and proteasome activity
Atrophy involves increased degradation of cellular components through the ubiquitin-proteasome pathway and autophagy, leading to decreased cell size. This reduces cellular metabolic demands. --- SECTION 2: MECHANISMS OF CELLULAR INJURY
Correct answer: B – Hypoxia and ischemia
Hypoxia and ischemia are the most common causes of cell injury, underlying conditions like myocardial infarction, stroke, and tissue infarcts throughout the body. ---
Correct answer: B – Mitochondrial swelling
Mitochondrial swelling and formation of amorphous densities in the mitochondrial matrix are among the earliest ultrastructural changes in reversible cell injury, reflecting impaired oxidative phosphorylation. ---
Correct answer: B – Lipid peroxidation
Free radicals cause cellular injury primarily through lipid peroxidation of membrane lipids, leading to membrane damage. They also damage proteins and DNA, but lipid peroxidation is the most significant mechanism. ---
Correct answer: C – Superoxide dismutase
Superoxide dismutase (SOD) converts superoxide radicals (O2-) to hydrogen peroxide (H2O2). Catalase and glutathione peroxidase then convert H2O2 to water. ---
Correct answer: B – Activation of destructive enzymes
Increased intracellular calcium activates phospholipases (damage membranes), proteases (break down proteins), endonucleases (damage DNA), and ATPases (deplete ATP), all contributing to cell death. --- SECTION 3: REVERSIBLE VS IRREVERSIBLE INJURY
Correct answer: C – Inability to reverse mitochondrial dysfunction
The point of no return in cell injury is marked by the inability to restore mitochondrial function even after resolution of the original injury. This leads to progressive loss of membrane integrity and cell death. ---
Correct answer: B – Failure of the Na+/K+ ATPase pump
Failure of the Na+/K+ ATPase pump due to ATP depletion leads to sodium and water influx into the cell, causing cellular swelling (oncosis). This is a characteristic feature of reversible injury. ---
Correct answer: C – Liver
The liver is most commonly affected by fatty change due to its central role in fat metabolism. Causes include alcohol, toxins, diabetes, obesity, and protein malnutrition. ---
Correct answer: B – Nuclear pyknosis
Nuclear changes (pyknosis, karyorrhexis, karyolysis) are hallmarks of irreversible injury and cell death. Cytoplasmic eosinophilia can occur in reversible injury due to ribosomal detachment. ---
Correct answer: C – Water accumulation causing cell swelling
Hydropic degeneration (vacuolar degeneration) refers to the accumulation of water in the cytoplasm causing cellular swelling. It represents an early manifestation of reversible cell injury. --- SECTION 4: TYPES OF NECROSIS
Correct answer: B – Preservation of tissue architecture
Coagulative necrosis maintains the basic tissue architecture for several days due to denaturation of structural proteins and enzymes. It is the most common type of necrosis and typical of ischemic injury in solid organs. ---
Correct answer: C – Brain infarction
Liquefactive necrosis occurs in brain infarctions due to the high lipid content and abundance of hydrolytic enzymes. It also occurs in bacterial infections due to release of lysosomal enzymes from neutrophils. ---
Correct answer: B – Tuberculosis
Caseous necrosis is characteristic of tuberculosis and some fungal infections. It has a cheese-like (caseous) appearance, combining features of coagulative and liquefactive necrosis. ---
Correct answer: A – Acute pancreatitis
Fat necrosis occurs when pancreatic enzymes (lipases) are released into the peritoneum in acute pancreatitis, breaking down fat cells. It also occurs in traumatic injury to adipose tissue such as breast tissue. ---
Correct answer: C – Immune-mediated vascular injury
Fibrinoid necrosis occurs in blood vessel walls in immune-mediated conditions like vasculitis, malignant hypertension, and autoimmune diseases. It appears as bright pink amorphous material on H&E staining. ---
Correct answer: B – Coagulative necrosis with bacterial overgrowth
Gangrene is not a specific type of necrosis but refers to coagulative necrosis of a large area (usually an extremity) with superimposed bacterial infection. Wet gangrene has a liquefactive component. SECTION 5: APOPTOSIS
Correct answer: C – It is energy-dependent
Apoptosis is an ATP-dependent active process of programmed cell death affecting single cells without inflammation. Necrosis is passive, affects groups of cells, and causes inflammation. ---
Correct answer: B – Nuclear and cytoplasmic shrinkage
Apoptotic cells show cell shrinkage, chromatin condensation (pyknosis), nuclear fragmentation, and formation of apoptotic bodies. The cell membrane remains intact initially. ---
Correct answer: B – Extrinsic pathway
The extrinsic pathway is initiated by binding of death ligands (like FasL, TNF) to death receptors (like Fas, TNFR1) on the cell surface, leading to caspase activation. ---
Correct answer: B – Bcl-2 family proteins
The intrinsic (mitochondrial) pathway is regulated by the Bcl-2 family of proteins. Pro-apoptotic members (Bax, Bak) promote apoptosis, while anti-apoptotic members (Bcl-2, Bcl-xL) inhibit it. ---