D236 Pathophysiology - Set 4 - Part 3

Correct Answer: Phosphate depletion

Rapid refeeding shifts phosphate intracellularly for metabolism causing dangerous hypophosphatemia affecting multiple organ systems critically.
Option a is incorrect because while glucose is involved, the dangerous complication is phosphate and electrolyte shifts.
Option c is incorrect because protein refeeding is gradual; the acute danger is electrolyte shifts, particularly phosphate.
Option d is incorrect because fat accumulation is slow; acute refeeding syndrome involves electrolyte depletion described.

Correct Answer: Osteoclast activators

Myeloma cells secrete factors activating osteoclasts causing bone resorption, lytic lesions, and pathological fractures characteristically.
Option a is incorrect because growth factors might be present but osteoclast activation specifically causes bone destruction.
Option c is incorrect because matrix proteins are destroyed, not secreted; osteoclast activators cause the damage.
Option d is incorrect because calcium is released from destroyed bone, not inhibited; osteoclast activation is key.

Correct Answer: Uric acid

Uric acid crystals precipitate in joints causing acute inflammatory arthritis with severe pain characteristic of gout.
Option a is incorrect because calcium phosphate causes pseudogout with different crystal appearance than uric acid gout.
Option c is incorrect because cholesterol deposits in vessels causing atherosclerosis, not the joint crystals described.
Option d is incorrect because cystine causes kidney stones in cystinuria, not the joint inflammation of gout.

Correct Answer: Protein degradation

Defective protein degradation causes alpha-synuclein accumulation forming Lewy bodies, leading to dopaminergic neuron death progressively.
Option b is incorrect because DNA replication issues cause different diseases; Parkinson's involves protein handling defects.
Option c is incorrect because lipid synthesis problems cause different disorders, not the protein accumulation in Parkinson's.
Option d is incorrect because carbohydrate metabolism defects cause different diseases than the protein aggregation described.

Correct Answer: Ceruloplasmin function

Defective ATP7B protein impairs ceruloplasmin function and biliary copper excretion, causing toxic accumulation in organs.
Option a is incorrect because transferrin transports iron, not copper; Wilson's involves copper handling specifically.
Option c is incorrect because ferritin stores iron; the problem in Wilson disease involves copper metabolism.
Option d is incorrect because hemosiderin is iron storage form; Wilson disease involves copper transport defects.

Correct Answer: Cortisol

Chronic cortisol elevation suppresses GnRH and gonadotropins, explaining stress-related reproductive dysfunction and amenorrhea commonly observed.
Option a is incorrect because adrenaline causes acute stress responses but cortisol mediates chronic reproductive suppression.
Option c is incorrect because while prolactin can suppress reproduction, cortisol is the primary stress hormone involved.
Option d is incorrect because oxytocin promotes bonding and reduces stress rather than suppressing reproductive function.

Correct Answer: Central sensitization

Fibromyalgia involves central pain processing abnormalities without peripheral inflammation, unlike inflammatory arthritis with joint damage.
Option a is incorrect because fibromyalgia doesn't cause joint destruction; it involves central pain processing dysfunction.
Option c is incorrect because fibromyalgia lacks autoantibodies that characterize autoimmune inflammatory arthritis conditions described.
Option d is incorrect because fibromyalgia lacks synovial inflammation; the pain results from central nervous system changes.

Correct Answer: Iron oxidation

Methemoglobinemia involves iron oxidation from ferrous to ferric state, preventing oxygen binding and delivery to tissues.
Option b is incorrect because the protein structure remains intact; the iron oxidation state change prevents function.
Option c is incorrect because heme isn't destroyed; the iron within heme is oxidized preventing oxygen binding.
Option d is incorrect because methemoglobinemia involves oxidation, not genetic globin mutations causing structural changes.

Correct Answer: Kidney

Kidney peritubular cells sense oxygen levels and produce erythropoietin stimulating bone marrow red cell production accordingly.
Option a is incorrect because while liver produces some erythropoietin in fetus, kidneys are primary adult source.
Option c is incorrect because spleen filters old red cells but doesn't produce the erythropoietin hormone described.
Option d is incorrect because bone marrow responds to erythropoietin but the kidney produces this hormone.

Correct Answer: Secretory phenotype

Senescent cells develop inflammatory secretory phenotype releasing cytokines that damage surrounding tissues and promote aging.
Option a is incorrect because while senescent cells stop dividing, their secretory activity causes tissue damage described.
Option c is incorrect because energy changes occur but the secretory phenotype specifically impacts surrounding tissues harmfully.
Option d is incorrect because DNA content doesn't define the harmful effects; the inflammatory secretions damage tissues.