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USMLE Step 1: Part 1 COPY > QBanks: Week of 01/15/17 > Flashcards

QBanks: Week of 01/15/17 Flashcards

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USMLE® Step 1 flashcards
1
Q

Describe the two forms of urachal abnormalities.

A

Complete patent urachus leads to “straw-colored” urine leaking out. Local irritation (from urine) also occurs.

Partial urachal sinuses lead to non-communicating cavities that can get infected and present with periumbilical tenderness.

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2
Q

The vitelline duct is also called ____________.

A

the omphalomesenteric duct

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3
Q

_____________ results from failure of the abdominal wall to close.

A

Gastroschisis

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4
Q

What statistical test is used to compare observed to expected outcomes?

A

The chi-square test (specifically for categorical data)

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5
Q

Describe the two stages of imaging tests used to evaluate cholecystitis.

A

Ultrasonography is the preferred initial test. Gallstones will appear as hyperechoic points in the hypoechoic lumen of the gallbladder.

If ultrasonography proves inconclusive, the definitive test is radionuclide biliary scan. In this test, an intravenously injected substance is selectively taken up by the liver and excreted in bile. If the cystic duct is occluded, then the gallbladder will not be visualized. This is the most specific test for evaluation of cholecystitis.

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6
Q

What lab values are classic for DIC?

A

Decreased fibrinogen
Increased D-dimers
Prolonged PT, PTT, and bleeding time

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7
Q

What chromosome is RB found on?

A

13 (think of the HPV proteins: E7 disrupts RB, and E6 disrupts p53… 6 + 7 = 13)

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8
Q

The protein that can cause Wilms tumor and gonadal dysgenesis is on which chromosome?

A

11

“Your kidneys allow you to make #1, and you have two kidneys, so… 11.”

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9
Q

What two cancers other than clear-cell carcinoma can be caused by VHL deletions?

A

Cerebellar hemangiomas and pheochromocytomas

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10
Q

What are the two classic signs of delirium?

A

Waxing and waning mental-status changes and inability to pay attention

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11
Q

Give the formula for standard error.

A

95% CI: (mean x 2)/√n

Note: for 99%, multiple the mean by 3. This means that as you increase n, the standard error (aka confidence interval) decreases and you can be sure that the true mean is within a narrower margin.

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12
Q

What’s the mechanism of topiramate?

A

It binds directly to the GABA-A receptor (like the conquistador directly shaking the Incan’s hand who is with the CAB-colored procession).

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13
Q

How long can the body’s stores of B12 last with no intake?

A

4-5 years

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14
Q

How can you differentiate B6 deficiency from B12 deficiency without knowing what kind of anemia or lifestyle patterns the patient has?

A

B6 presents with dermatitis and lowered seizure threshold.

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15
Q

What is the only monosaccharide to bypass the regulated step in glycolysis?

A

Fructose

Fructose gets phosphorylated to fructose-1 phosphate and then enters as glyceraldehyde.

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16
Q

Where is glucose-1 phosphate in the glycolytic pathway?

A

Galactose gets metabolized to galactose-1 phosphate which then gets metabolized to glucose-1 phosphate. G1P can then get rearranged to G6P.

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17
Q

Where can mannose-6 phosphate enter the glycolytic pathway?

A

As fructose-6 phosphate

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18
Q

True or false: aldosterone makes the urine more alkaline.

A

False. It makes the urine more acidic and the blood more alkaline.

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19
Q

Increasing GFR does what to natriuresis?

A

It increases natriuresis.

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20
Q

What two forms of hemoglobin are found in adults?

A

A: alpha-2, beta-2
A2: alpha-2, delta-2

(You know A, but to remember the structure of A2 just think that ADults have Alpha and Delta.)

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21
Q

Describe buspirone.

A

Buspirone is a partial agonist at the 5HT1A receptor used to treat anxiety. It has not sedative, euphoric, or muscle relaxant effects. It takes several weeks to become effective.

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22
Q

Taking opiates can cause colicky RUQ pain due to _________________.

A

stimulated contraction in the sphincter of Oddi that leads to cholestasis

(Think of the biliary-tree-shaped palm tree in the Sketchy video!)

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23
Q

What is the innominate artery?

A

The brachiocephalic trunk

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24
Q

What is subclavian steal syndrome?

A

Narrowing of the subclavian artery proximal to the branching of the vertebral artery can lead to anterograde flow through the ipsilateral vertebral artery.

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25
Q

What is Cushing’s triad and what does it indicate?

A

Hypertension, bradycardia, and bradypnea

Increased ICP

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26
Q

What electrolyte abnormality can carbamazepine cause?

A

SIADH (remember the guy in the car with the soda on his head)

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27
Q

Which part of the antibody activates complement?

A

The region just lateral and proximal to the disulfide bridges

Note: the most proximal region is where the CD16 receptor binds.

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28
Q

What finding can suggest myopathy from an autoimmune/endocrine source?

A

Hypothyroidism can cause myopathy, and the classic finding is myoedema due to impaired calcium intake into the sarcoplasmic reticulum.

The finding is a small lump that arises when you tap the muscle with a hammer.

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29
Q

Aortic regurgitation is heard as a ___________ murmur.

A

early diastolic

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30
Q

The subthalamic nucleus ___________ the globus pallidus interna.

A

excites

The GPI is an inhibitory nucleus, so without the excitation from the STN the thalamus goes wild.

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31
Q

What are the two first choices for treatment of status epilepticus?

A

Benzodiazepine

Phenytoin

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32
Q

Once again, review the effects on the action potential of the different subclasses of class I antiarrhythmics.

A

Ia: prolongs phases 2 and 3 and decreases the slope of phase 1. (Think of the prom queen throwing back the curtain and lengthening the action potential.)

Ib: shortens phases 2 and 3 and decreases the slope of phase 1. (Think of Libby pulling the curtain closed.)

Ic: does not affect phases 2 or 3. (Think of the untouched curtain.)

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33
Q

What is junctional escape rhythm?

A

When the AV node takes over control of the heart and the QRS occurs before P (a sign of digoxin toxicity)

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34
Q

What electrolyte imbalance is commonly seen in digoxin toxicity?

A

Hyperkalemia

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35
Q

Hypoalbuminemia alone cannot cause _____________.

A

pulmonary edema

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36
Q

Fat emboli can cause ________________.

A

ARDS

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37
Q

What two tissues are injured in ARDS?

A

Pneumocytes and pulmonary endothelium

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38
Q

What are the conduction velocities of the heart from fastest to slowest?

A

Purkinje fibers
Atrial muscle
Ventricular muscle
AV node

(“Park At Ventura Avenue.”)

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39
Q

Why does the area around the insertion of the pulmonary veins often cause atrial fibrillation?

A

Because that area functions like a sphincter –preventing flow backward into the lungs –and has different electrical properties than the rest of the atrium.

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40
Q

What disorders predispose people to osteosarcoma?

A

Paget’s
Li-Fraumeni
Retinoblastoma
Radiation

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41
Q

Osteosarcoma has a ____________ age distribution.

A

bimodal (common in adolescents and those older than 60)

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42
Q

How might osteosarcoma present on x-ray?

A

With reactive bone formation at the cortex, lifting of the periosteum, mixed lysis/sclerosis, a sunburst of bone growth, and Codman’s triangle –a wedge of bone growing off the cortex

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43
Q

What is osteopetrosis and how might it present on x-ray?

A

Lack of osteoclast function leads to generalized sclerosis of bone. On x-ray, the bones will appear sclerotic with fractures possible.

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44
Q

What esophageal disorder presents with a sensation of dysphagia or something stuck in the throat with complete absence of abnormal findings?

A

Globus sensation

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45
Q

Substernal goiter can lead to ___________.

A

difficulty breathing, if the thyroid grows fast enough

Note: difficulty swallowing is unlikely to occur given the posterior position of the esophagus.

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46
Q

True or false: pseudobulbar palsy presents with on-and-off dysphagia.

A

False. Pseudobulbar palsy results from neurologic conditions and presents with continuous dysphagia, dysarthria, and dysphonia.

47
Q

Which inflammatory cell type is associated with gout?

A

Neutrophils

48
Q

______________ is a uricosuric agent.

A

Probenecid (like Cid throwing the kid out)

49
Q

Which supplement is contraindicated in pregnancy except in cases where the patient may be deficient?

A

Vitamin A

It is teratogenic, particularly in the first trimester, so pregnant women should not consume excess amounts. Furthermore, deficiency is uncommon in those without malabsorptive GI concerns who eat a normal, varied diet.

50
Q

Which vitamin is a safe anti-emetic for pregnant women?

A

B6

“Pyridoxine = Puke-no-more, ma’am.”

51
Q

A woman presents with recent fever. Her colleague was sick. This woman has no pharyngeal exudate, but a nasopharyngeal swab comes back positive. What drug might she be prescribed?

A

Oseltamivir (a neuraminidase inhibitor)

52
Q

What kind of proteins often undergo posttranslational cleavage?

A

Proteins that get secreted from the cell

They often have signal sequences that allow them to get to the endoplasmic reticulum or Golgi apparatus, and once they arrive they cleave that peptide.

53
Q

Where are procollagen peptidases?

A

Outside the cell

Collagen gets secreted and then procollagen peptidase cleaves it, thereby allowing it to be assembled.

54
Q

If you ran a cell that has undergone apoptosis through electrophoresis, what finding might you notice?

A

DNA laddering

Cells undergoing apoptosis cleave their DNA in 180-base segments – at spots that would bind to histones –and this can be seen on gels.

55
Q

Cells that survive despite absence of pro-growth interleukins might have evaded what cellular function?

A

Apoptosis

56
Q

Where are M1 receptors found?

A

In the brain (like the first motorcyclist in the Sketchy scene)

57
Q

Activation of which autonomic receptor leads to release of nitric oxide?

A

M3 (like the third motorcyclist in the Sketchy scene –his exhaust pipe is labeled “Nitric Oxide”)

M3 receptors are in the gut and smooth muscle. These receptors mediate erection.

58
Q

How often should those with diabetes have neurologic sensation testing?

A

Annually

59
Q

What translocation is common in acute lymphocytic leukemia?

A

t(12;21)

“ALL is common in 12-year-olds with trisomy 21.”

60
Q

What chromosome is BCL-2 on?

A

18

Follicular lymphoma is t(14;18).

61
Q

Which cells secrete GM-CSF?

A

Macrophages, lymphocytes, fibroblasts, and granulocytes

62
Q

In response to a viral infection, macrophages and B cells secrete _______________.

A

interferon alpha

63
Q

Which cells secrete IL-2?

A

Only activated T lymphocytes. IL-2 is a potent T-cell stimulator that activates other T cells. As such, it’s important that this step be regulated by antigen presentation.

64
Q

Which intercellular adhesion molecules are calcium-dependent?

A

Cadherin proteins are calcium-dependent, so both desmosomes and cadherin junctions need extracellular calcium.

65
Q

Describe molluscum contagiosum.

A
  • A papular rash caused by poxvirus that resembles BCC
  • Histologically characterized by inclusion bodies
  • Pruritic
  • Can appear on the face, trunk, or anogenital area
66
Q

In posterior and anterior dislocations of the knee, what structure is at risk of tearing?

A

The popliteal artery! It is closely adherent to the posterior surface of the knee, so displacement can tear it.

67
Q

Caesarean section raises risk for _______________.

A

postpartum endometritis; with surgery on the uterus, normal cervicovaginal flora can invade the uterus and cause infection a couple days later

68
Q

What kind of receptor is HER2/neu?

A

It is an epidermal growth factor receptor, so it is a tyrosine kinase.

69
Q

Chronic cocaine abuse can lead to _______________.

A

thinned nasal mucosa with perforations

70
Q

How does heminephrectomy alter GFR?

A

Immediately GFR will drop after a heminephrectomy (to approximately 50%). Within about 4-6 weeks, however, hemodynamic and structural changes allow the one kidney to compensate to about 80% of the pre-surgery GFR.

71
Q

Specifically, what does NO do to the penis?

A

It stimulates relaxation of smooth muscle in the corpus cavernosa (via increased cGMP) that allows blood to enter.

72
Q

Craniopharyngiomas arise from _______-derm.

A

ecto

73
Q

Distill the pancreatic secretions to the easiest version to memorize.

A

Pancreatic centroacinar secretions start out with NaHCO3, but if secretion is slow enough then bicarb gets replaced with Cl.

(Pancreas is salty when slow.)

74
Q

What’s the difference between PTSD and acute stress disorder?

A

Only time: ASD is less than one month and PTSD is greater than one month.

75
Q

What is the formula for relative risk?

A

(incidence in exposed) / (incidence in unexposed)

76
Q

How can you find the number needed to treat (NNT)?

A

NNT = reciprocal of the risk reduction

For instance, if 40% of people treated with a new drug survive and 20% of people treated with the old drug die, then the NNT is 5 (because 1/.2 = 5).

77
Q

How can herpetic encephalitis present?

A

With fever and temporal lobe symptoms: anosmia, seizure, bizarre behavior

78
Q

True or false: those with acute intermittent porphyria can develop abdominal port-wine stains.

A

False! They develop port-wine colored urine!

79
Q

What can worsen the neurologic symptoms of cobalamin deficiency?

A

Administration of folate alone

80
Q

Someone with diplopia and fatigability might have hyperplasia in what organ?

A

Thymoma

81
Q

What happens to sodium levels in DKA?

A

They drop! Remember the formula: for every increase of glucose by 100 mg/dL, sodium decreases by 1.6 mEq/L.

82
Q

What kind of drug is isoproterenol?

A

Nonselective beta-agonist

83
Q

______________ are at increased risk of intraventricular hemorrhage, also called ______________.

A

Premature infants; germinal matrix hemorrhages

This is a disorder in which the ventricular layer bleeds. It produces non-communicating hydrocephalus, thus premature infants present with bulging fontanelles.

84
Q

What antibiotic can cause pulmonary fibrosis?

A

Nitrofurantoin

85
Q

What is genetic heterogeneity?

A

When a phenotype can be caused by different genetic mutations

86
Q

How do nitroglycerins affect end-diastolic heart volume and heart rate?

A

Because NO dilates large veins, it decreases EDHV which then increases HR

87
Q

Describe the clinical presentation of pseudohypoparathyroidism.

A

Due to end-organ resistance to parathyroid hormone, children develop profound hypocalcemia and hyperphosphatemia even with high amounts of parathyroid hormone.

Signs are skeletal abnormalities, failure to grow, short fingers, and a round face.

88
Q

In which cells does iron accumulate in hemochromatosis?

A

Parenchymal macrophages

89
Q

If a person has impetigo from a burn, what organism most likely caused it?

A

Staph. aureus

Note: Pseudomonas often infects burns, but it does not cause impetigo. It causes ecthyma gangrenosum, pyoderma, folliculitis, and nail-bed infections.

90
Q

How do efflux pumps work?

A

They usually pump antibiotics out of the cytosol through proton co-transporters (because protons are much higher in concentration within cells). Thus, decreasing the pH of the growth media can inhibit efflux pumps.

Remember: tetracyclines and fluoroquinolones are often pumped out of bacteria.

(To remember the protons, think of the Sketchy bike pump spraying out acid and eating through the asphalt of the bike race.)

91
Q

What symptoms might a patient have if they have a COL1A mutation?

A

Easily broken bones –osteogenesis imperfecta

92
Q

What hand sign can indicate achondroplasia?

A

A space between the 3rd and 4th digits

93
Q

What is preproinsulin?

A

It is the original insulin molecule that is directed to the endoplasmic reticulum. The N-terminal signal-recognition particle gets cleaved and leaves proinsulin in the ER to be secreted.

94
Q

List two treatments for hyperhidrosis.

A

Sytemic anticholinergic medications (e.g., oxybutynin) and disruption of the thoracic sympathetic ganglia

95
Q

How will pulmonary embolism affect pH, O2, and CO2?

A

PE will cause V/Q mismatch with resulting hypoxemia. That will trigger hyperventilation which will lead to excess removal of CO2 but failure to bring the O2 to normal levels. As such, PE leads to hypoxemia with respiratory alkalosis.

96
Q

What genetic abnormalities lead to Prader-Willi and Angelman?

A

PW: maternal disomy of 15
A: paternal disomy of 15

(“AngelMAN presents with two chromosomes from the MAN.”

97
Q

In a callous, which layer of the epidermis proliferates?

A

The stratum corneum

Essentially, the stratum corneum contains keratinized cells that are the most protective and help protect the basal layers.

98
Q

_______________ works by prematurely terminating prokaryotic peptide chains.

A

Puromycin

99
Q

The three germinal layers are derived from the ____-blast.

A

epi

(Just think: both hypoblast and epiblast end in -blast, but epi- is three letters exactly like the three germinal layers!)

100
Q

Which class of medication produces the most miosis in a denervated eye?

A

Direct parasympathomimetics (such as pilocarpine)

Indirect parasympathomimetics like physostigmine require acetylcholine release from the nerve terminal, so in a denervated eye they will produce little miosis.

101
Q

Spermatoceles typically arise from the ____________.

A

caput of the epididymis

102
Q

Acanthosis nigricans can present with what cancer?

A

Gastric adenocarcinoma

103
Q

What structure do Aspergillus fungi have?

A

Germinal bodies with an asexual hyphae

104
Q

Which cells get enlarged in FSGS?

A

Epithelial cells

105
Q

Berger disease is also called _______________.

A

IgA nephropathy

106
Q

A stillborn child is revealed to have hypoplasia in the hands and uterine didelphys. What gene likely caused this mutation?

A

HOXA13

“It affects your Hands and the Os of your cerviX –the unlucky 13.”

107
Q

Decreasing afterload does what to contraction velocity?

A

Increases it

108
Q

How does vitamin D affect phosphate levels?

A

It increases intestinal absorption of both calcium and phosphate.

109
Q

In a PCR, why does the primer reanneal instead of the other strand of DNA?

A

Excess primers are added and they effectively out compete the other DNA strand.

110
Q

The maxillary sinus and ethmoid sinus drain into the ______________, while the nasolacrimal duct and eustachian tube drain into the _____________.

A

middle nasal meatus; inferior nasal meatus

Maxillary = Middle

111
Q

Large infarctions of the middle cerebral artery can produce what kind of visual disturbances?

A

Homonymous hemianopsia

112
Q

Describe the two medications that inhibit leukotrienes.

A

Zileuton inhibits lipoxygenase (it ZILEnces the enzymes)

Montelukast inhibits the leukotriene receptor (it MOuNTs the receptor)

113
Q

Allelic heterogeneity is _______________.

A

when two different mutations at the same locus can have the same phenotype

USMLE Step 1: Part 1 COPY (243 decks)

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