D236 Pathophysiology - Set 3 - Part 2

Correct Answer: Plaque accumulation

Lipid-rich plaques accumulate in arterial walls, narrowing vessels and potentially rupturing to cause thrombosis and infarction.
Option a is incorrect because atherosclerosis involves wall thickening from plaque, not thinning that characterizes aneurysms instead.
Option c is incorrect because while vasospasm can occur, plaque buildup is the primary pathological process in atherosclerosis.
Option d is incorrect because valves don't form in arteries; atherosclerosis involves plaque deposition narrowing vessel lumens.

Correct Answer: Enzyme deficiency

Phenylketonuria results from phenylalanine hydroxylase enzyme deficiency, preventing conversion to tyrosine causing toxic phenylalanine accumulation.
Option a is incorrect because PKU involves metabolic enzyme deficiency, not structural protein abnormalities affecting tissues.
Option c is incorrect because receptor abnormalities cause different disorders; PKU specifically involves enzyme deficiency described.
Option d is incorrect because transport defects cause different diseases; PKU results from enzymatic conversion failure.

Correct Answer: Tight junctions

Tight junctions create impermeable seals between epithelial cells, controlling paracellular transport and maintaining barrier function effectively.
Option a is incorrect because gap junctions allow small molecule communication between cells, not creating barrier seals.
Option c is incorrect because desmosomes provide mechanical strength through adhesion but don't seal spaces between cells.
Option d is incorrect because hemidesmosomes anchor cells to basement membrane, not sealing intercellular spaces described.

Correct Answer: Invasion and metastasis

Malignant tumors invade surrounding tissues and metastasize to distant sites while benign tumors remain localized.
Option a is incorrect because some benign tumors grow rapidly while some cancers grow slowly; invasion distinguishes them.
Option c is incorrect because while cancers often look abnormal, invasion and metastasis definitively distinguish malignancy.
Option d is incorrect because size doesn't determine malignancy; small cancers can metastasize while large benign tumors remain localized.

Correct Answer: Myasthenia gravis

Myasthenia gravis involves autoantibodies blocking acetylcholine receptors at neuromuscular junctions, causing weakness and fatigability characteristically.
Option a is incorrect because multiple sclerosis involves central nervous system demyelination, not neuromuscular junction antibodies.
Option c is incorrect because muscular dystrophy involves genetic muscle protein defects, not autoimmune receptor blockade.
Option d is incorrect because ALS involves motor neuron degeneration, not antibody-mediated neuromuscular junction dysfunction.

Correct Answer: Cortisol hormone

Chronic cortisol elevation from stress suppresses immune responses by inhibiting inflammatory mediators and lymphocyte function.
Option a is incorrect because melatonin regulates sleep cycles and has some immune effects but isn't the primary stress hormone.
Option c is incorrect because oxytocin promotes bonding and reduces stress rather than suppressing immunity during stress.
Option d is incorrect because prolactin stimulates milk production and has minor immune effects compared to cortisol.

Correct Answer: Passive natural

Passive natural immunity occurs when maternal antibodies transfer naturally through breast milk, providing temporary infant protection.
Option a is incorrect because active natural immunity develops from actual infections, not antibody transfer from mother.
Option c is incorrect because active artificial immunity results from vaccination stimulating the recipient's immune response directly.
Option d is incorrect because passive artificial immunity involves administering prepared antibodies medically, not natural transfer described.

Correct Answer: Liver organ

The liver accumulates iron in hemochromatosis, leading to cirrhosis and potential hepatocellular carcinoma from oxidative damage.
Option a is incorrect because while kidneys can be affected, the liver bears primary iron storage burden in hemochromatosis.
Option c is incorrect because the spleen filters blood but isn't the primary site of pathological iron accumulation.
Option d is incorrect because the bladder isn't significantly affected by iron overload compared to liver damage.

Correct Answer: Lysosomal dysfunction

Tay-Sachs results from lysosomal enzyme deficiency causing ganglioside accumulation in neurons, leading to neurodegeneration progressively.
Option a is incorrect because mitochondrial dysfunction causes energy metabolism disorders, not the storage disease described here.
Option c is incorrect because peroxisomal disorders affect fatty acid metabolism differently than the lysosomal storage pattern.
Option d is incorrect because ribosomal dysfunction affects protein synthesis, not the cellular material accumulation described.

Correct Answer: Apoptosis evasion

Cancer cells develop mechanisms to evade apoptosis, surviving despite DNA damage that would kill normal cells.
Option a is incorrect because cancer cells often have defective DNA repair, not enhanced repair mechanisms described.
Option c is incorrect because cancer cells are poorly differentiated, and this doesn't explain survival despite damage.
Option d is incorrect because cancer cells often have increased metabolism to support rapid growth, not reduced.

Correct Answer: Collagen protein

Corticosteroids inhibit collagen synthesis and increase degradation, weakening skin structure causing striae and easy bruising.
Option a is incorrect because while elastin provides stretch, collagen provides primary structural strength affected by steroids.
Option c is incorrect because keratin forms hair and nails; collagen loss causes the skin fragility described.
Option d is incorrect because fibrin forms blood clots; the skin changes result from collagen loss, not fibrin.

Correct Answer: Brief vasoconstriction

Transient vasoconstriction occurs immediately after injury before vasodilation, initiating the hemodynamic changes of inflammation.
Option a is incorrect because increased permeability follows initial vascular diameter changes in the inflammatory sequence.
Option b is incorrect because vasodilation follows the brief initial vasoconstriction phase in acute inflammatory response.
Option d is incorrect because leukocyte adhesion occurs after vascular changes create appropriate conditions for cell migration.

Correct Answer: Multifactorial inheritance

Multifactorial disorders require both genetic susceptibility and environmental factors interacting to manifest disease phenotype clinically.
Option a is incorrect because simple Mendelian disorders follow predictable patterns without requiring environmental triggers for expression.
Option c is incorrect because chromosomal disorders result from chromosome abnormalities regardless of environmental factors present.
Option d is incorrect because single gene mutations cause disease directly without requiring additional environmental triggers.

Correct Answer: Shortening occurs

Telomeres shorten with each division until critically short length triggers senescence, limiting normal cell replication.
Option a is incorrect because telomeres shorten unless telomerase is active; lengthening doesn't occur normally with division.
Option c is incorrect because methylation changes affect gene expression but aren't the telomere change limiting replication.
Option d is incorrect because while mutations can occur, progressive shortening is what limits replication capacity.

Correct Answer: Eosinophil cells

Eosinophils increase specifically during parasitic infections and allergic responses, releasing toxic granules against parasites effectively.
Option a is incorrect because neutrophils respond primarily to bacterial infections, not parasites or allergies specifically.
Option c is incorrect because basophils contribute to allergic responses but eosinophils show more specific elevation patterns.
Option d is incorrect because monocytes become macrophages for general phagocytosis, not specific parasite or allergy response.

Correct Answer: Low oxygen states

Deoxygenation causes hemoglobin S polymerization, deforming red cells into sickle shapes that obstruct vessels painfully.
Option a is incorrect because high oxygen prevents sickling; it's low oxygen that triggers the shape change.
Option c is incorrect because glucose levels don't directly trigger sickling; oxygen tension is the primary factor.
Option d is incorrect because hypoglycemia doesn't cause sickling; deoxygenation drives the pathological shape change described.

Correct Answer: Pattern of features

Syndromes are recognized patterns of signs and symptoms occurring together, while diseases have defined pathological processes.
Option a is incorrect because both syndromes and diseases can vary in severity; the distinction is conceptual organization.
Option c is incorrect because treatment response doesn't distinguish syndromes from diseases in medical classification systems.
Option d is incorrect because both syndromes and diseases can have genetic or non-genetic causes equally.

Correct Answer: Type III collagen

Type III collagen forms initially during healing, providing temporary structure before replacement with stronger type I collagen.
Option a is incorrect because type I is mature collagen deposited later, replacing the initial type III framework.
Option c is incorrect because type IV collagen forms basement membranes, not the initial wound healing matrix.
Option d is incorrect because type VII forms anchoring fibrils, not the primary healing collagen described here.

Correct Answer: Increased venous pressure

Right heart failure increases systemic venous pressure, forcing fluid into interstitial spaces causing peripheral edema formation.
Option a is incorrect because arterial pressure changes don't directly cause the peripheral edema from venous congestion.
Option c is incorrect because lymphatic pressure changes cause different edema patterns than cardiac failure edema described.
Option d is incorrect because oncotic pressure typically decreases in some conditions; venous pressure drives cardiac edema.

Correct Answer: Phagocytosis process

Phagocytosis involves membrane extensions engulfing large particles or cells, bringing them into the cell for digestion.
Option a is incorrect because pinocytosis involves drinking small amounts of fluid, not engulfing large particles described.
Option c is incorrect because exocytosis releases materials from cells rather than bringing particles inside for processing.
Option d is incorrect because osmosis involves water movement across membranes, not particle engulfment mechanisms described.