NBME Exam Review Flashcards
what is the effect of opioids binding the following opioid receptor types:
a. mu
b. delta
c. kappa
d. sigma
mu: analgesia, reward, adverse CNS/PNS effects (respiratory depression)
delta: analgesia, reward, neuronal adaptations leading to addiction
kappa: analgesia, oppose reward signaling (–> dysphoria under stressful conditions)
sigma: regulate higher-order functions such as memory and drug dependence
what is the role of the following cell types?
a. luteal cell
b. granulosa cell
c. theca externa
d. theca interna
a. luteal cell: present in corpus luteum, derived from granulosa cells of pre-ovulatory follicle; secrete estrogen and progesterone
b. granulosa cell: convert androgens (received from theca interna) into estradiol via aromatase
c. theca externa: make up loose connective tissue (fibroblasts, macrophages, smooth muscle)
d. theca interna: generate androstenedione from cholesterol
what are the stages of the cell cycle?
G0: cell cycle arrest
G1: enzymes necessary for DNA replication are synthesized (everything is duplicated except chromosomes)
S: DNA replication
G2: integrity of duplicated genome is checked, growth phase
M: mitosis + cell division
most common cause of mouth sores, exacerbated by spicy/acidic foods, dental work, or emotional stress
aphthous ulcers: painful, round, shallow oral ulcers; common in adolescence/young adulthood
of what is geographic tongue a feature, and how does it appear?
geographic tongue: feature of psoriasis in children, looks like maze of white linear patches
how do Koplik spots appear?
bright red macules with bluish-white center on buccal mucosa
due to measles infection, will be accompanied by fever+cough+coryza+conjunctivitis and maculopapular rash starting on head/neck –> trunk (excluding palm/soles)
with what is leukoplakia associated?
leukoplakia: white plaques in mouth which cannot be scaped off
due to underlying EBV infection, common in patients with HIV or malignancy
oral white patches with stellate appearance =
oral lichen planus
cross-section of liver showing innumerable lesions is most likely due to metastasis from where?
colorectal carcinoma (CRC)
remember - primary cancer produces single lesions, while metastasis produces many
why should ACE inhibitors be used with caution in patients with renal artery stenosis?
cause dilation of efferent arterioles –> transient decrease in GFR
in patients with renal artery stenosis, nephron is dependent on efferent vasoconstriction (via angiotensin II) to maintain adequate filtration pressure
with which classes of antibiotics (2) are aminoglycosides synergistic?
aminoglycosides (gentamicin, neomycin, amikacin, tobramycin, streptomycin) inhibit 30s bacterial ribosome
synergistic with penicillins, which inhibit peptidoglycan cross-linking of bacterial wall, and monobactams (aztreonam), which also target peptidoglycan cross-linking function (but require O2)
which muscle supinates the forearm?
biceps brachii: supinates the forearm + flexes the elbow
what causes neonatal hypoglycemia in children born from diabetic mothers?
decreased gluconeogenesis - human placental lactogen produced by the placenta increases maternal insulin resistance –> increased glucose in maternal circulation
fetal hyperglycemia causes fetus to produce excess insulin and decrease gluconeogenesis
at birth, fetus continues to synthesize insulin but is no longer exposed to maternal blood glucose levels –> hypoglycemia
melanocortin 2 receptor =
ACTH receptor
[motor/parasympathetic] fibers from the ____ nerve innervation all muscles of the pharynx except the ______ muscle
motor fibers from the vagus nerve innervation all muscles of the pharynx except the stylopharyngeus muscle (innervated by glossopharyngeal nerve)
how does actinic keratosis vs lentigo maligna appear?
actinic keratosis (pre-malignant to squamous cell carcinoma): light pink, gritty texture, in areas of sun exposure
lentigo maligna (subtype of melanoma): slow-growing, brown-black, scaly, irregular borders, in areas of sun exposure of elderly patients (appears like melanoma.. because it is !)
tumor biopsy shows malignant, small, blue neoplasm expressing cytokeratin, chromogranin, and synaptophysin - what kind of tumor is this?
pulmonary small cell carcinoma
don’t be confused if this biopsy is found outside the lung - could be metastasis! (esp. brain)
which part of the intestines is most often affected by diverticulosis?
sigmoid colon - has small diameter, predisposing to greater intraluminal pressure
diverticulosis = mucosa + submucosa herniates through muscular layer
pediatric patient w/ increased urinary excretion of alanine, isoleucine, leucine, phenylalanine, tryptophan, and valine
what is the dx, and for which vitamin deficiency are they at risk for?
dx = Hartnup disease: AR defect in amino acid transporter (kidney and intestines) –> deficiency of neutral amino acids
at risk for niacin (B3) deficiency (niacin is derived from tryptophan) –> dementia, dermatitis, diarrhea
screening tests require high [sensitivity/specificity], while confirmatory tests require high [sensitivity/specificity]
screening tests require high sensitivity (able to detect disease)
confirmatory tests require high specificity (able to rule out disease)
fixed split S2 =
atrial. septal. freaking. defect.
due to increased SV of RV –> delayed closure of pulmonary valve
somatic symptom disorder vs conversion disorder vs factitious disorder vs malingering and pleasedontmakemewasteanymorecardsdonthis
somatic symptom disorder: preoccupation with 1+ somatic symptoms (may or may not originate from underlying disease), patient spends a lottt of time trying to “cure” these
conversion disorder: aka functional neurological disorder, these are gonna be sensory or motor “dysfunctions” (not explained by clinical findings)
factitious disorder: goal is primary gain (to be cared for)
malingering: goal is secondary gain (disability payments)
Infant presenting with lethargy, vomiting, poor feeding, hepatomegaly, and seizures. Labs show increased levels of argininosuccinate, citrulline, and ammonia. What enzyme is defective?
dx = argininosuccinic aciduria: mutation in argininosuccinate lyase (ASL), which converts argininosuccinate to arginine
these are intermediates in the urea cycle - therefore, results in defective conversion of ammonia to urea
where can the great saphenous vein be palpated?
great saphenous vein - longest vein in body, runs along medial aspect of leg, can be palpated along the anterior aspect of the medial malleolus of the ankle
18yo F being evaluated for amenorrhea. She has never had a menstrual period. She is 6ft and has normal breast and external genitalia development. There is no axillary or pubic hair. What is the most likely karyotype?
dx = androgen insensitivity syndrome: 46,XY (M) genotype with F phenotype
testes are present and produce testosterone, absent internal F genitalia, rudimentary vagina
which vitamin is used in the treatment of psoriasis?
Vitamin D - plays a role in immune modulation via binding nuclear TF
MOA of sildenafil
inhibits cGMP-specific phosphodiesterase-5 (PDE-5) –> increase in NO (and therefore vascular dilation) in the corpus cavernosa (pair of richly vascularized erectile bodies in shaft)
used to treat ED
urea vs uric acid
urea: metabolic product of cystine, soluble in water, reabsorbed in nephron to create hyperosmolar gradient surrounding loop of Henle - does NOT cause AKI or hyperuricemia
uric acid: NOT water soluble and may crystallize, causes many problems
what is the FEV1/FVC ratio in obstructive vs restrictive lung disease?
obstructive = FEV1/FVC < 0.7 (DECREASED)
restrictive = FEV1/FVC > 0.8 (INCREASED)
child presenting with bilateral aching in the temples, cognitive impairment, mood swings and irritability, hallucinations, and broad-based/ataxic gait most likely has had chronic exposure to what type of toxin?
inhalants (ex, glue) - distinguished from other toxic manifestations by headache and cerebellar dysfunction
decreased urinary output following episode of hypotension = what kind of kidney injury? Which area of the kidney is most heavily affected by the prolonged hypotension?
acute tubular necrosis (ATN) - most heavily affects PCT, which is why sloughing of tubular cells leads to muddy brown casts in urine
what are LINE sequences
LINE = long interspersed nuclear element
method of bacterial genetic variation through transposable elements (segment of DNA moves from chromosome to plasmid)
Child w/ migraine-like headaches, vomiting, and multiple L-sided focal seizures. She has had hearing loss since 11yo. Her mother and maternal grandmother have high-tone deafness. PE shows weakness in R upper and lower extremities. Serum and CSF lactic acid are increased. Dx?
mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) - mutation in mitochondrial tRNA
female with taut, smooth facial skin without wrinkles should raise suspicion of…
systemic sclerosis (scleroderma): autoimmune collagen deposition and progressive fibrosis, more commonly affects females
what is the rate-limiting step of peripheral nerve regeneration?
slow anterograde axonal transport of newly synthesized cytoskeleton and cytoplasmic proteins to axon terminal
the spinothalamic tract is organized somatotopically such in the spinal cord such that lateral region controls ______, while the anterior region controls ______
lateral = pain/temp
anterior = crude touch/pressure
most common bacteria (3) to cause pneumonia in patients with chronic granulomatous disease (NADPH oxidase deficiency)? most common fungal cause?
- Staphylococcus species
- Burkholderia cepacia
- Nocardia species
also at risk for fungal infections by Aspergillus
which cancers (2) most commonly metastasize to vertebrae?
breast and prostate
[just think of the vertebral column connecting these two organs]
which topical medication used for primary open angle glaucoma may cause SOB and decreased FEV1?
beta blockers (timolol) - beta inhibition in the ciliary body reduces formation of aqueous humor
relatively contraindicated in patients with asthma
how can chronic autoimmune (Hashimoto) thyroiditis be differentiated from granulomatous thyroiditis on PE?
Hashimoto’s: thyroid is firm, nodular, diffusely enlarged, symptoms of hypothyroidism
granulomatous (de Quervain): follows viral illness, symptoms of hyperthyroidism, thyroid is painful and tender
deficiency of which of the following can lead to symptoms of peripheral neuropathy and retinitis?
a. Apo A-I
b. Apo A-II
c. Apo B
d. Apo C
e. Apo E
c. Apo B: essential component of LDL, IDL, and VLDL - required for normal absorption/trafficking of lipids to/from intestines and liver
mutations in MTP gene lead to absent/reduced Apo B –> chronic malabsorptive diarrhea + deficiencies of DAKE vitamins –> neurological manifestations
what is the consequence of lack of scrotal attachment to the gubernaculum?
undescended testes due to inability of gubernaculum to guide the testis through the inguinal canal to the scrotum
what is the infectious cause of epididymitis with thick, green urethral discharge?
Neisseria gonorrhoeae
epididymitis presents with fever, purulent urethral discharge, and pain localized to 1 testis which may be alleviated by elevation of that hemiscrotum
[Chlamydia can also cause epididymitis, but would not cause green discharge]
transfer of electrons from NADH to coenzyme Q = which complex of ETC?
complex I - transfer generates a proton gradient
transfer of electrons from ubiquinol to cytochrome c = which complex of ETC?
complex III - transfer generates a proton gradient
which organelles are the site of combination of antigen and MHC I vs MHC II synthesis, respectively?
endoplasmic reticulum = site of combining target peptides with MHC I
endosomes = site of combining antigens and MHC II
[note MHC II are synthesized in ER, but trafficked to late endosomes]
which of the following is consistent with pneumonia?
a. muffled whispered sounds over R lower lung field
b. increased tactile fremitus over R lower lung field
c. vesicular breath sounds over R lower lung field
b. increased tactile fremitus over R lower lung field - relies on increased sound wave transmission and vibrations through consolidated lung tissue (as compared with normal, aerated lung tissue)
muffled whispers are normal - clear and easily audible indicates pneumonia
vesicular breath sounds are normal
woman with unexplained thrombocytopenia a month after a viral respiratory infection =
immune thrombocytopenic purpura (ITP): anti-GpIIb/IIIa antibodies bind platelets –> peripheral destruction of platelets
diagnosis of exclusion, often follows viral illness
function of L-type Ca2+ channel vs Na+/Ca2+ exchanger vs ryanodine receptor
L-type (dihydropyridine channel): voltage-gated, opens during phase 2, coupled with ryanodine receptor
ryanodine receptor: releases Ca2+ from SR to cytoplasm
Na+/Ca2+: brings Na+ into cytoplasm and Ca2+ out of cytoplasm to stop contraction
what cell type is predominant in induration following PPD skin test?
MACROPHAGES - CD8 T cells are there too but are NOT predominant
macrophages are also predominant in lungs of patients with TB
what is the mechanism by which oxidizing free radicals generated by acetaminophen overdose damage hepatocytes?
acetaminophen overdose –> CYP-mediated reactions to NAPQI, which generates free radicals
free radicals damage hepatocytes through lipid peroxidation in cell membranes, oxidative damage to proteins, and strand breaks in DNA
what are the paraneoplastic syndromes of small cell lung carcinoma? (3)
- ACTH - Cushing syndrome
- SIADH
- LEMS (Lambert-Eaton)
decubitus ulcers =
pressure sores
harsh, high-pitched holosystolic murmur that radiates over precordium and a palpable thrill at the L sternal border =
ventricular septal defect
[atrial septal defect = fixed split S2 + low grade ejection murmur]
what are the symptoms of I-cell disease?
developmental delay/delayed growth, coarse facial features, generalized hypotonia, restricted skeletal development, hepatosplenomegaly, cardiac structural defects, corneal clouding, dwarfism
[AR inheritance, defect in mannose residue phosphorylation of lysosomal hydrolases]
which of the following contributes to lateral rotation of the thigh?
a. gluteus minimus
b. piriformis
c. rectus femoris
b. piriformis
other lateral rotators include obturator internus and externus, gemelli, and quadratus femoris
[gluteus minimus - hip abduction and internal rotation]
which cells secrete inhibin in males vs females, and what is its direct action?
F - granulosa cells
M - Sertoli cells
acts to inhibit FSH at the level of the pituitary
what is the mechanism of hypercalcemia in multiple myeloma?
malignant plasma cell clones locally secrete IL-1, TNFa, and RANK-L to stimulate osteoclasts
portal HTN can be transmitted through which of the following veins?
a. hepatic
b. short gastric
c. suprarenal
b. short gastric
other options drain into IVC (systemic, not portal)
tumor biopsy stains positive for desmin - what type of tissue is it?
MUSCLE
desmin = intermediate filament
MOA of each of the following?
a. flucytosine
b. amphotericin B/ nystatin
c. echinocandins
d. fluconazole
a. flucytosine - inhibition of DNA and RNA synthesis
b. amphotericin B/ nystatin - pore formation in fungal cell membrane
c. echinocandins - prevention of cross-linking of beta-glucans in cell wall
d. fluconazole - inhibits production of ergosterol via inhibiting cytochrome P450-dependent demethylation reactions
what gene is mutated in AR vs AD polycystic kidney disease?
AR (juvenile) - fibrocystin
AD (adult) - polycystin (PKD1 or PKD2)
the rate of shortening within a muscle is governed by:
a. rate of Na/K ATPase activity
b. amount of muscle phosphocreatine
c. rate of cross-bridge recycling
d. frequency of action potentials
c. rate of cross-bridge recycling
What is the difference between embolism and thrombus?
An embolus is a particle or mass that flows through the bloodstream. A thrombus is a blood clot in a blood vessel. If a thrombus breaks off, it can become an embolus.
what are the 3 points of narrowing along the course of the ureter?
- ureteropelvic junction of the renal pelvis and ureter
- ureterovesical junction as ureter enters posterior bladder
- pelvic inlet when ureter crosses the external iliac vessels
what is derived from the following?
a. diencephalon
b. telencephalon
c. mesencephalon
d. metencephalon
e. prosencephalon
prosencephalon –> telencephalon (cerebral hemispheres, lateral ventricles) + diencephalon (thalamus, hypothalamus, third ventricle)
mesencephalon –> midbrain + cerebral aqueduct
metecephalon –> pons, cerebellum, fourth ventricle
function of clathrin-coated pits vs COPII-coated pits
clathrin-coated: main structures on cell membrane involved in receptor-mediated endocytosis
COPII: involved in molecular transport of substances from ER to Golgi apparatus
congenital diaphragmatic hernia is due to impaired development of the ______ membrane
pleuroperitoneal membrane
relative risk (RR) is considered significant when the confidence interval (CI) [does/doesn’t] cross 1.0
RR is significant when CI DOES NOT cross/include 1.0
[CI including 1.0 = not statistically significant]
case-control vs cohort vs case series
case-control: patients with/without DISEASE are matched, and exposure data is collected –> odds ratio (OR)
cohort: patients with/without EXPOSURE are matched, and outcome data is collected –> relative risk (RR)
case series: for rare diseases, follow progression of patient disease and treatment - useful for characterizing natural history of disease or response to treatment, do not imply cause/effect or test a hypothesis
what is produced by acidophils vs basophils
The acidophils secrete GH (somatotropes) and prolactin (mammotropes).
Basophils secrete TSH (thyrotropes), LH (gonadotropes), FSH (gonadotropes), and ACTH (corticotropes)
patient presenting with N/V, epigastric abdominal pain radiating to the back, and bruising of both flanks =
acute pancreatitis - often in patient with history of gallstones, alcoholism, trauma, hypertriglyceridemia, or hypercalcemia
Grey-Turner sign = bruising of flanks
Cullen sign = bruising around umbilicus
patients with methylmalonic acidemia should avoid _____, and some patients may respond to supplementation of _____
patients with methylmalonic acidemia should avoid protein, and some patients may respond to supplementation of B12 (cobalamin)
methylmalonyl-CoA mutase catalyzes conversion of methylmalonyl-CoA to succinyl-CoA, which is important for metabolism of branched-chain AA (isoleucine, valine, threonine, methionine), and B12 is a cofactor
which veins can provide an alternate route for blood from upper extremities and head/neck to return to IVC in the setting of superior vena cava syndrome?
intercostal and internal mammary veins
SVC syndrome presents with cough, swelling of face/neck, increased JVD, upper extremity swelling, distended chest vein collaterals, and conjunctival edema
patient w/ PMH of cerebellar hemangioblastoma and retinal angiomas is most likely to develop what type of renal cancer?
renal adenocarcinoma (renal clear cell carcinoma) - comprised of tubular epithelial cells
dx = vHL syndrome
how are levels of the following affected by B12 deficiency?
a. methionine
b. methylmalonate
a. methionine: DECREASED due to decreased conversion of homocysteine to methionine
b. methylmalonate: INCREASED due to decreased conversion of methylmalonyl-CoA to succinyl-CoA
holoprosencephaly is a congenital malformation of:
a. diencephalon
b. mesencephalon
c. prosencephalon
d. rhombocephalon
e. telencephalon
c. prosencephalon - origin of cortical hemispheres, lateral ventricles, thalamus, hypothalamus
not telencephalon because it is named following differentiation from prosencephalon, not before
hyperacute rejection is caused by…
preformed antibodies which activate compliment and cause thrombosis
what type of brain bleed can result in sudden LOC w/ pinpoint pupils and decorticate posturing?
intraparenchymal - associated with uncontrolled HTN, often occur in putamen, thalamus, pons, cerebellum
decorticate posturing = above red nucleus
the target of the influenza vaccine is…
hemagglutinin
[neuraminidase is target of oseltamivir]
MOA albendazole
binds to tubulin and inhibits microtubule polymerization
MOA fluconazole
inhibition of cytochrome P450-dependent demethylation system - inhibits formation of ergosterol (part of fungal cell membrane)
MOA flucytosine
inhibition of DNA/RNA synthesis
what is the consequence of perforation of an anterior vs a posterior duodenal ulcer?
anterior –> pneumoperitoneum
posterior –> hemorrhage of gastroduodenal artery
which of the following describes the location of the AV node?
a. posteroinferior region above the opening of the coronary sinus
b. superoanterior region above the limbus of the fossa ovalis
c. superoposterior region posterior to the fossa ovalis
a. posteroinferior region above the opening of the coronary sinus
what are the lab findings of euthyroid sick syndrome?
abnormalities in thyroid function testing that occur in setting of acute systemic illness (likely part of acute phase response)
decreased free T3, normal/low T4 and free T4, normal TSH
clinically euthyroid, do not have symptoms of hypothyroidism
anti-mitochondrial antibodies =
primary biliary cholangitis: autoimmune disorder of intralobular bile ducts
presents in middle-age women w/ pruritis, fatigue, cholestasis, jaundice, hepatosplenomegaly, DAKE deficiency
histology of Takayasu arteritis shows…
graulomatous inflammation
[large vessel vasculitis affecting young female patients, weak pulses caused by narrowing of aortic arch/proximal great vessels]
