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USMLE Step 1 > UWorld_4.3 > Flashcards

UWorld_4.3 Flashcards

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USMLE® Step 1 flashcards
1
Q

Pharmacokinetic characteristics of inhaled gases/anesthetics

A
  • onset of action correlates with blood solubility (blood/gas partition coeff.)
    • high blood/gas = blood saturates slowly ==> slower equilibration w/brain & slower onset of action
    • low blood/gas = blood saturates rapidly ==> faster equilibration w/braind and rapid onset of action
  • MAC = ~potency (inversely related)
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2
Q

Resistance for circuits in parellel & series

A
  • [parallel] 1/RT = 1/R1 + 1/R2 + 1/R3 + ….
  • [series] RT = R1 + R2 + R3 + ….
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3
Q

Hb actions @ lungs vs. peripheral tissues

A
  • @ lungs: increased O2 binding ==> release of CO2 and H+ = “Haldane effect”
  • @ periphery: high [CO2] & [H+] ==> O2 unloading
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4
Q

Characteristics of Acute Intermittent Porphyria + tx

A
  • porphobilinogen deaminase deficiency
  • usually asymptomatic ==> acute abdominal pain + N/V + neuro sx + reddish-brown urine (or recurring ab pain)
  • tx =
    • dextrose/glucose prep
    • heme prep
    • both ==I ALA synthase
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5
Q

What are smelly sweat glands called?

A

apocrine glands

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6
Q

Gram + rods that form “medusa” heads/serpentine ==> dx?

A
  • bacillus anthracis
  • pulmonary anthrax = woolsorters disease
    • widening mediastinum (hemmorhagic mediastinitus)
  • virulence = antiphagocytic capsule w/D-glutamate instead of polysacc
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7
Q

“Hot tub folliculitis”

A
  • self-limited P.aeuruginosa infection from hot tub/pools that do not have adequate chlorination
  • ==> papulopustular rash w/oxidase-positive gram-neg rods
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8
Q

Main energy source that drives gluconeogenesis

A
  • GTP: faciliates OAA ==> PEP by PEPCK
  • rxn that produces GTP = Succinyl CoA ==> Succinate
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9
Q

Methotrexate SE

A
  • stomatitis = painful mouth ulcers
  • hepatotoxicity = hepatitis, fibrosis, cirrhosis
  • myelosuppression ==> increased infection risk
  • B-cell lymphomas
  • pulmonary fibrosis
  • contraindicated in pregnancy
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10
Q

Encapsulated organisms

A
  • H. influenza
  • S. pneumo
  • N. meningitis
  • Salmonella
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11
Q

Indirect vs. Direct vs. Femoral hernias

A
  • Indirect
    • most common @ male infant
    • enters inguinal ring
    • lateral to inferior epigastric vessels
    • due to persistent processus vaginalis & failure of closure of inguinal ring
  • Direct
    • most common @ older men
    • bulges through Hesselbach’s triangle
    • medial to inferior epigastric vessels
    • ==> external inguinal ring
    • due to weakness in transversalis fascia
  • Femoral
    • most common @ women
    • potrudes through femoral ring
    • medial to femoral vessels
    • inferior to inguinal ligament
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12
Q

Characteristics of acute pancreatitis

A
  • blockage ==> digestion of adipose by lipase
    • calcium deposition + edema = acute interstitial
  • if inflammation continues ==> acute necrotic pancreatitis
    • chalky white fat necrosis + hemorrhage
    • activation of proteolytic enzymes
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13
Q

Chronic lymphedema ==> increased risk for?

A

angiosarcoma

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14
Q

Terbanifine: MOA

A
  • inhibits squalene oxidase ==> inhibition of fungal wall formation
  • use = dermatophytoses; e.g. tinea corporis
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15
Q

branched-chain alpha ketoacid dehydrogenase coenzymes

A
  • coenzymes = “TLC For Newborn (w/MSUD)”
    • Thiamine pyrophosphate
    • Lipoate
    • CoA
    • FAD
    • NAD
  • other enzymes w/same coenzymes
    • pyruvate dehydrogenase
    • alpha-ketoglutarate dehydrogenase
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16
Q

Schilling test results

A
  1. Administer parenteral B12 + oral radiolabeled B12
    1. high urinary excretion = normal absorption <== low dietary intake
    2. low urinary excretion = poor absorption
  2. Administer parenteral B12 + oral radiolabeled B12 + IF
    1. high urinary exretion = low IF is cause of poor absorption
    2. low urinary excretion = poor absorption is due to pancreatic/bowel problem
17
Q

Gram (+) bacteria w/polar granules staining w/aniline dyes ==> dx?

A
  • diptheria AB toxin = EF2 adp-ribosylation
18
Q

Low vs. High frequency sound hearing @ inner ear

A
  • high freq = @ base of cochlea, near oval and round window
  • low freq = @ apex of cochlea, near helicotrrema
19
Q

Ethambutol: MOA

A
  • inhbiits arabinosyl transferae ==> inhibition of carbohydrate polymerization necc. for synthesis of TB cell wall
  • not effective against non-TB bacteria
20
Q

Intrafusal vs. golgi tendon organs @ muscles

A
  • GTOs responsd to m. tension ==> connect to inhibitory interneurons of anterior horn motor
    • (sudden relax in elevated tension)
  • Intrafusal = responsd to passive strectch
    • innervated by Ia and II sensory fibers
    • DTRs
21
Q

location of HMG-CoA

A

mitochondria of hepatocytes ==> cholesterol formation

22
Q

Digoxin: MOA, use

A
  • ==I Na-K-ATPase pump @ cardiac ventricular myocytes ==> Ca2+ accumulation ==> increased contractility
  • acts on vagus nerve ==> decreased AV node condution
  • 2nd line in Afib w/RVR
23
Q

Polycythemia vera association

A

JAK2 mutation = non-receptor tyrosine kinase

24
Q

Characteristics of abetalipoproteinemia

A
  • defect in ApoB synthesis ==> inability to form chylomicrons & VLDL
  • ==> fat accumulation @ epithelium of small intestine ==> foamy/clear appearace
25
Q

Characteristics of contracture formation

A
  • during wound healing: excessive MMP activity + myofibroblast accumulations @ wound margins ==> contracture
  • produce deform @ wound/surround tissue
  • most often @ palms, soles, ant. thorax, serious burn sites
26
Q

Common cause of congenital bilateral agenesis of vas deferens

A

CF

27
Q

Presentation of Reye synrome

A
  • viral illness + tx with aspirin
  • hepatic dysfxn ==>
    • vomiting + hepatomegaly
    • elevated ALT, AST, ammonia, bili, prolonged PT/PTTT
    • biopsy = microvesicular steatosis w/out necrosis or inflammation
  • encephalopathy = due to hyperammonia
28
Q

CN IX fxn

A
  • motor = stylopharyngeus
  • parasym
    • parotid gland secretion
  • sensory
    • post. 1/3 tongue
    • typamic membrane/eustachian tube
    • tonsillar region
    • upper pharynx
    • carotid body/sinus
29
Q

PRPP synthase activation ==> increased pathway activity and consequences?

A
  • ==> increased purine synthesis (+degredation) ==> gout
30
Q

Target in gout tx

A
  • PMNs
  • via NSAIDs (COX inhibition)
  • or (if NSAIDs contraindicated) then Colchichine: MT inhibition
31
Q

(Tetrahydrobiopterin) BH4 cofactor importance

A
  • inc synthesis of tyrosine, DOPA, serotonin, NO
  • dihydrobiopterin reductase = enzyme that takes BH2 ==> BH4 in order for enzymes in this pathway to fxn
32
Q

Trousseau’s syndrome + similar process in heart

A
  • Trousseau = migratory thrombophlebitis
  • similar = nonbacterial thrombotic endocarditis <==hypercoagulable state
33
Q

Complication of tx of neonatal respiratory distress syndrome

A
  • ==> retinopathy due to retinal neovascularization
34
Q

Cause of amennorhea in anorexia

A
  • loss of pulsatile secretion of GnRH from hypothalamus
35
Q

MEN 1 =

MEN 2A =

MEN 2B =

A
  • MEN 1 = “3Ps” = parathyroid, pituitary, pancreas
  • MEN 2A = pheo, med carc thyroid, parathyroid
  • MEN 2B = pheo, med carc thyroid, oral and intestinal mucosal neuromas

USMLE Step 1 (97 decks)

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