D236 Pathophysiology - Set 3 - Part 3

Correct Answer: Peptidoglycan thickness

Gram-positive bacteria have thick peptidoglycan walls retaining crystal violet stain, while gram-negative have thin walls.
Option a is incorrect because while membrane differences exist, peptidoglycan thickness determines gram staining characteristics primarily.
Option c is incorrect because both gram-positive and negative bacteria can have flagella; wall thickness distinguishes them.
Option d is incorrect because capsule formation occurs in both types; peptidoglycan layer determines staining properties.

Correct Answer: Platelet adhesion

Von Willebrand factor mediates platelet adhesion to damaged vessels; its deficiency impairs primary hemostasis causing bleeding.
Option a is incorrect because fibrin formation involves different clotting factors; vWF specifically affects platelet function described.
Option c is incorrect because thrombin activation involves the coagulation cascade, not the platelet adhesion defect present.
Option d is incorrect because calcium is important for clotting but vWF deficiency specifically impairs platelet adhesion.

Correct Answer: Renal system

Microalbuminuria indicates early diabetic kidney damage, detectable before clinical symptoms or other organ involvement appears.
Option a is incorrect because while neuropathy is common, kidney changes are often detectable earlier through urine testing.
Option c is incorrect because cardiovascular changes develop but renal microalbuminuria is typically the earliest detectable change.
Option d is incorrect because musculoskeletal complications are late manifestations compared to early renal changes detected.

Correct Answer: Intestinal metaplasia

Barrett esophagus involves intestinal metaplasia replacing normal esophageal epithelium, increasing adenocarcinoma risk significantly over time.
Option a is incorrect because the change is from squamous to intestinal epithelium, not squamous metaplasia development.
Option c is incorrect because the tissue undergoes metaplastic change, not atrophy which would involve tissue loss.
Option d is incorrect because fibrous replacement would be scarring; Barrett's involves epithelial type change instead.

Correct Answer: Vitamin B1

Thiamine deficiency in alcoholics causes Wernicke encephalopathy with confusion, ataxia, and eye movement abnormalities characteristically.
Option a is incorrect because B12 deficiency causes different neurological problems including peripheral neuropathy and cognitive changes.
Option c is incorrect because B6 deficiency causes different symptoms; thiamine specifically causes Wernicke encephalopathy described.
Option d is incorrect because folate deficiency causes megaloblastic anemia and neural tube defects, not Wernicke syndrome.

Correct Answer: Extrinsic pathway

Prothrombin time tests the extrinsic pathway involving tissue factor and factor VII, monitoring warfarin anticoagulation.
Option a is incorrect because the intrinsic pathway is tested by partial thromboplastin time, not prothrombin time.
Option c is incorrect because while the common pathway is involved, PT specifically tests extrinsic pathway function.
Option d is incorrect because platelet function tests are different; PT tests the coagulation cascade extrinsic pathway.

Correct Answer: Protein misfolding

Prions are misfolded proteins that induce normal proteins to misfold, propagating disease without nucleic acids.
Option a is incorrect because prions aren't viruses and don't integrate into genomes; they're purely protein-based.
Option c is incorrect because prions aren't bacterial products; they're host proteins with abnormal conformation causing disease.
Option d is incorrect because while inflammation occurs, the primary mechanism is protein misfolding propagation described.

Correct Answer: Low calcium

Kidney disease reduces calcium absorption and increases phosphate, triggering parathyroid hormone release to normalize calcium.
Option a is incorrect because high calcium would suppress parathyroid hormone, not cause the hyperparathyroidism described.
Option c is incorrect because potassium doesn't directly regulate parathyroid hormone secretion like calcium does primarily.
Option d is incorrect because sodium imbalances don't trigger secondary hyperparathyroidism; calcium regulation drives this response.

Correct Answer: Dystrophin complex

Dystrophin protein complex defects destabilize muscle cell membranes, causing progressive degeneration and weakness in muscular dystrophy.
Option a is incorrect because mitochondrial myopathies are different; muscular dystrophy involves structural protein defects primarily.
Option b is incorrect because sarcoplasmic reticulum stores calcium; dystrophin complex provides membrane stability described.
Option d is incorrect because myosin is contractile protein; dystrophin complex defects cause the membrane instability.

Correct Answer: Same cell targeting

Autocrine signals affect the same cell that produces them, while paracrine signals affect nearby different cells.
Option a is incorrect because both act locally; the distinction is whether signals affect the producing cell itself.
Option c is incorrect because both can use similar signal molecules; the target cell relationship distinguishes them.
Option d is incorrect because receptor specificity exists in both; self versus neighboring cell targeting distinguishes them.