Freediver plunges into icy water; HR drops while MAP rises to preserve brain flow. Which autonomic reflex best explains the bradycardia?
A) Trigeminal-vagal
B) Baroreceptor unloading
C) Bainbridge reflex
D) β1 upregulation
#CoreStepPrep #USMLE #MedStudent #MedSchool
3
19F perfumer trainee: amenorrhea anosmia; MRI absent olfactory bulbs. Failed puberty is due to which defect? A) GnRH neuron migration B) Aromatase excess C) 5α-reductase deficiency D) Leydig cell aplasia #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
4
Shiny Jessy 💗 retweeted
Toddler: coarse facies, cloudy corneas, ↑ plasma lysosomal enzymes; fibroblasts have inclusions.
Failed step?
A) M6P tag in Golgi
B) COPII budding from ER
C) Importin nuclear entry
D) Clathrin uncoating
#CoreStepPrep #USMLE #MedStudent #MedSchool
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1
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Ultramarathoner pops ibuprofen, then gets oliguria bland urine after a GI bug. Which renal hemodynamic change best explains ↓GFR? A) Afferent constriction B) Efferent dilation C) ↑Mesangial relax D) ↑Kf #CoreStepPrep #USMLE #MedStudent #MedSchool
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Postpartum pt insists her baby was swapped by an identical impostor; neuro exam normal. Which misidentified link is disrupted? A) Face recognition-affect B) Hippocampal-LTP C) Broca-Wernicke D) Papez olfaction #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
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Jun 15
Age 4: vaginal bleeding jagged café-au-lait; LH/FSH low. Ovarian cells bypass axis control. Defect? A) Gsα locked on B) Giα locked on C) JAK-STAT gain D) IP3/Ca loss #CoreStepPrep #USMLE #MedStudent #MedSchool
7
Jun 15
Teen fencer has anosmia, no puberty; LH/FSH low despite normal pituitary MRI. What failed embryologic event? A) GnRH neuron migration B) POMC cleavage C) Thyroglobulin iodination D) 21-hydroxylation #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
15
Jun 15
Falconer on steroids: brain abscess cavitary pneumonia; sputum has branching weakly acid-fast rods. Host defect raising risk? A) NADPH oxidase B) C5-C9 deficiency C) IgA deficiency D) TLR4 mutation #CoreStepPrep #USMLE #MedStudent #MedSchool
22
Jun 15
Post-BCG infant has disseminated mycobacteria; DHR normal. Defective pathway? A) IL-12→IFN-γ axis B) C5-9 MAC assembly C) CD40L switching D) AIRE deletion #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
20
Jun 15
Infant w anemia, fractures & CN palsies has marble-dense bones; osteoclasts present but lacuna acidification fails. Defect?
A) Carbonic anhydrase II
B) Type I collagen
C) RANKL signaling
D) ALP mineralization
#CoreStepPrep #USMLE #MedStudent #MedSchool
11
Jun 14
Newborn has choking/cyanosis with feeds; NG tube coils in upper pouch, gas in stomach. Which embryologic error? A) TE septum deviation B) Urachus persistence C) Failed midgut return D) Vitelline duct remnant #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
8
Jun 14
Dialysis pt opens a new AV fistula; minutes later HR rises and MAP falls despite ↑venous return. Which change drives ↑CO? A) ↓TPR B) ↑Afterload C) ↓Contractility D) ↑Blood viscosity #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
12
Jun 14
Floppy newborn later has hyperphagia & obesity. Two intact chr15s are both maternally derived. Mechanism?
A) Uniparental disomy
B) Anticipation
C) Loss of imprinting
D) Trinucleotide repeat
#CoreStepPrep #USMLE #MedStudent #MedSchool
8
Jun 14
Newborn drools/chokes w feeds; prenatal polyhydramnios gastric air. Failed partitioning of which embryonic structure? A) TE septum B) Urorectal septum C) Septum transversum D) Neural crest #CoreStepPrep #USMLE #MedStudent #MedSchool
7
Jun 14
17M with delayed puberty, small testes, and no axillary hair can't smell burnt popcorn after a dorm microwave fiasco. Expected pattern?
A) ↓ pulsatile GnRH
B) ↑ inhibin B
C) ↑ testosterone
D) ↑ LH surges
#CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
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Jun 13
Teen has woolly hair, palmoplantar keratosis & exertional syncope; RV fibrofatty change suggests Naxos dz. Mutated junctional protein?
A) Plakoglobin
B) Integrin α6β4
C) Keratin 14
D) Connexin 26
#CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
6
Jun 13
Arizona spelunker has fever, erythema nodosum, hilar LAD; spherules packed with endospores in tissue. Which lab form is infectious?
A) Arthroconidia
B) Spherules
C) Budding yeast
D) Germ tubes
#CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
26
MONA✨ retweeted
Jun 13
Teen with eczema, staph cold abscesses, pneumatoceles, scoliosis & retained baby teeth has very high IgE. Which defect drives poor Th17 differentiation? A) STAT3 B) BTK C) WASp D) CD18 #CoreStepPrep #USMLE #MedStudent #MedSchool #Step1
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1
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