NBME CBSE ACTUAL TEST QUESTIONS AND ANSWERS (QUIZ BANK WITH ALL THE CORRECT ANSWERS) (USMLE STEP 1) MEDICAL EXAMINATION A+

2024 NBME CBSE ACTUAL TEST
QUESTIONS AND ANSWERS 100% SURE
Type II pneumocytes - correct answer=surfactant (*lecithin*)
Proliferate after injury
Type I progenitors
*Neonatal Respiratory Distress Syndrome*

Polio live v killed vaccine - correct answer=Killed = Salk = IgG

Live = Sabin = IgG + IgA
- can be shed in feces

Neonatal Respiratory Distress:
Etiology + Tx - correct answer=Maternal DM (*high insulin*)
or C-section (*low cortisol*)
TX: *dexamethasone* before birth

Lung maturity determined with - correct answer=Amniocentesis of Phospholipids (*type II
pneumocytes)
L >> S

Type I pneumocytes - correct answer=Squamous gas diffusion

Elastase in lungs - correct answer=macrophage: *lysosomes*
PMN: *azuronphilic granules*

Elastin stretches and recoils due to - correct answer=Lysine interchain crosslinks

air pressure and
intrapleural pressure at FRC - correct answer=Air pressure = 0
Intrapleural pressure = -5

Pulm Vasc Resistance is lowest during - correct answer=Exhale of Tidal Volume

Lung Compliance is decreased by - correct answer=LHF, pulmonary edema,
pulmonary fibrosis

Lung Compliance is increased by - correct answer=emphysema, age

Obesity affects ERV and FRC - correct answer=DECREASE
ERV & FRC

Blood flow/min (pulmonary v systemic) - correct answer=pulmonary = systemic

,Anatomic pulmonary shunting - correct answer=Bronchial circulation causes
*decreased PO2 in LA/LV*
than in pulmonary capillaries

More ventilation is at the - correct answer=BASE

O2-Hgb dissociation LEFT shift - correct answer=basic, cold, low 2,3 BPG
low pO2 (compensatory erythrocytosis)

O2-Hgb dissociation RIGHT shift - correct answer=low pH, high 2,3BPG, high T
HOT, ACIDIC

CO2 transport to lungs - correct answer=*carbonic anhydrase*
Cl shift
*Haldane*: CO2 released to lung
(*Bohr*: O2 release to tissue)

CO poisoning causes - correct answer=carboxyhemoglobin
no affect on PaO2

Cyanide poisoning causes - correct answer=lactic acidosis

How to treat cyanide poisoning - correct answer=*Amyl nitrite* --> Methemoglobin
THEN *Thiosulfate* (hydroxycobalamin)

Normal A-a gradient - correct answer=5-15

Hypoventilation: Heroin OD or high altitude

Increased A-a gradient - correct answer=*Diffusion impairment* (fibrosis)
*R-L shunt* (aspiration, ARDS)
*V/Q mismatch* (pulmonary edema

AT --> AT II
where and how - correct answer=ACE
(- high in sarcoidosis)
In small pulmonary bV

C5a induces what - correct answer=PMN influx (ie: in lungs)

Korotkoff sound - correct answer=BP cuff - appear and disappear
in inflation/deflation

Pulsus Paradoxus - correct answer=10mmHg difference in
Korotkoff sound

,Pulsus Paradoxus occurs in - correct answer=Cardiac Tamponade

Kussmaul sign - correct answer=JVP rises *during inspiration*
Constrictive Pericardiditis

Restrictive/Interstitial Lung Disease:
A-a, FVC, FEV1, EFR - correct answer=Airway widening due to *radial traction* from fibrosis
*increase Aa*
decreased FVC & FEV1
*Increased EFR*

Sarcoidosis - correct answer=*Th1 *noncaseating granulmona
bilateral hilar adenopathy
increased *ACE*
increased IL2, IFNg
1-a-hydroxylase in macrophages: vit D --> *HyperCa*

Hyper Ca causes - correct answer=stones, thrones, groans, psych overtones

1-a-hydroxylase in macrophages - correct answer=PTH independent conversion of
Calcifediol to *calcitriol* (bioactive Vit D)

Vit D --> Hyper Ca

Idiopathic pulmonary fibrosis - correct answer=*Honeycomb* pattern
loss of Type 1 pneumocytes
*hyperplasia Type II* pneumocytes

Goodpasture - correct answer=HS II
Auto-Ab against BM destroys lung alveoli (*restrictive*) and renal glomeruli

Obstructive Lung Disease - correct answer=DECREASED FEV1, Decreased FVC
increased RV, FRC, TLC
**different shape

COPD - correct answer=PMN, mo, CD8

*V/Q mismatch:* O2 induced hypercapnia;
physio dead space

Myeloperoxidase causes - correct answer=Green sputum/pus

Do not give O2 supplement to - correct answer=COPD patient
Decreased stimulation of
*carotid bodies* = decreased RR

, TX COPD with - correct answer=*Fluticasone* (glucocorticoid)
inhibit cellular reaction

a1-antitrypsin deficiency - correct answer=Serine protease inhibitor

*LIVER*
*LUNG*: inc PMN elastase --> emphysema

Asthma dx - correct answer=*Methacholine* (maCh) challenge
= induce bronchoconstriction
to reduce FEV1
+ test = Airways ARE reactive

B2 agonist MOA - correct answer=B2 (Gs) --> AC --> increase *cAMP*

Corticosteroid MOA - correct answer=inhibit cytokine synthesis
suppress T lymphocyte

mACh Antagonist ("tropium") MOA - correct answer=*inhibit Vagal* via ACh
--> decreased Ca

OSA causes - correct answer=pulmonary HTN and RHF
increases EPO which worsens HTN

EPO can do what
on Cardiovascular - correct answer=worsen HTN

Pulmonary Arterial HTN - correct answer=*BMPR2*
High *endothelin*, Low NO
SMC hypertophy, fibrosis, narrow lumen
*P2 louder* than A2

When is P2 louder than A2 - correct answer=Pulmonary Artherial Hypertension

TX pulmonary arterial hypertension - correct answer=Endothelin-R antagonist:
- Bo*sentan*, Ambi*sentan*
PGEi (inc cGMP):
- Silden*afil*

Pulmonary Embolism - correct answer=*perfusion defect* (V/Q mismatch)
sudden SOB + calf swelling
Hypoxemia --> *Hyperventilate *
--> *Respiratory Alkalosis *
--> Metabolic compensation in 2 days

dx pulmonary embolism - correct answer=*D-dimer* test