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Aa Shit You Don't Know > NBME 24 > Flashcards

NBME 24 Flashcards

1
Q

Which protein delivers antigen to MHC I in the RER?

A

TAP: (transporter associated w/ antigen processing)

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2
Q

How does squatting during a tet spell help?

A

By squatting, SVR is increased. Therefore, the blood that is about to go from R—>L across the VSD is facing increased pressure on the left side, so it shoots up the pumonary artery like it should to get oxygenated.

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3
Q

What are Downey cells and when are they seen?

A

CD8+ Tcells that are seen in EBV infection. EBV infects B cells, but causes “atypical lymphocytes”, which are the CD8 t cells.

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4
Q

STEMI: how will it affect the SVR, Pulm. Vascular Resistance, and PCWP?

A

Increased SVR and PCWP, but decreased pulmonary vascular resistance
The heart is failing, so it isnt pumping enough blood out, thus the PCWP increases. Body needs more output, so you get a sympathetic response. This constricts peripheral vasculature, but dilates vessels in the lungs. Hence increased SVR but decreased PVR

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5
Q

What is mifePRISTONE?

A

Competitive inhibitor of progestins at progesterone receptors. Causes termination of pregnancy (mifepristone with misoprostol).

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6
Q

“Virus forms plaques on cultured human laryngeal cells but rapidly loses its ability to form plaques when dried or exposed to a pH of 5.0” what are they trying to tell you?

A

This is description of an enveloped virus

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7
Q

What structure does the parotid gland pass through. Hint this structure compresses the cheeks against the teeth and is used for acts such as blowing air out of mouth.

A

Buccinator

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8
Q

Why are the genetic inheritance of DM, type 1 and schizophrenia similar?

A

Monozygotic twins have a 50% chance of getting schizo/DM1 if their twin is affected.

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9
Q

Vimentin, desmin, cytokeratin, lamins, glial fibrillary acidic protein (GFAP), neurofilaments are all example of what cytoskeletal element?

A

These are intermediate filament proteins that maintain 2-d network on the inner surface of the nuclear membrane.

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10
Q

What 3 muscles close the jaw?
Which muscle opens the jaw?
Innervation of all?

A

3 muscles that close the jaw is Masseter, Temporalis, Medial Pterygoid
1 muscle that opens the jaw is the Lateral Pterygoid.
All are innervated by trigeminal nerve

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11
Q

Which structure is at risk for injury during ligation of the infundibulopelvic ligament (suspensory ligament)?

A

Ureter courses retroperitoneally, close to gonadal vessels in suspensory ligament

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12
Q

How does Botulinum toxin work?

A

Cleaves SNARE protein. prevents release of stimulatory** (ACh) signals at NM junction. flaccid paralysis is the result.

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13
Q

VANCEN: things that cause cutaneous flushing

A

Vancomycin, Adenosine, Niacin, Ca+2 channel blockers, Echinocandins, Nitrates

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14
Q

What is the main indication for the 5-HT1a receptor antagonist, Buspirone?

A

Generalized anxiety disorder. Remember buproprion is different: it is an atypical antidepressant that inhibits NE and DA reuptake.

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15
Q

Spina Bifida is due to failure of fusion of the neuropores. If patient has spina bifida occulta, they might have absence of spinous processes in that region. What causes the lack of spinous processes?

A

Failure of sclerotome fusion

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16
Q

What does the HOX gene regulate in embryogenesis?

A

Transcription: specifically segmental organization of embryo in a craniocaudal direction. So if mutated you get appendages in the wrong location

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17
Q

Patient has bp cuff placed around arm, it occludes blood flow. Blood flow increases by 50% over the next 3 minutes and then decreases back down to normal value. Explain

A

Cuff occlusion causes cells and tissue distal to cuff to continue consuming ATP (ATP—>ADP), but no fresh blood will be delivered to clear what is accumulating (ADP and other metabolites) ADP=Adenosine, is itself a proxy of consumption and drives vasodilation of arteries. Increasing ADP/Adenosine in a local environment is a signal to the body that a lot of consumption is occuring there; thus, arteries and arterioles naturally dilate to increase blood flow rates and sweep away metabolic byproducts.

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18
Q

What is the direct action of histamine on lymphatic smooth muscle via stimulation of H1?

A

Increased contractile activity, leading to increased lymph flow

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19
Q

Patient is hypoglycemic, lactic acidotic, has ketonemia, and metabolic acidosis. IV administration of glycerol or fructose do not help. But galactose does. Explain

A

This is fructose bisphosphatase deficiency. Glycerol/fructose don’t help because they enter the gluconeogenesis pathway below fbisphosphatase. Galactose is broken down by galactokinase, then Galactose-1-phosphate uridyltransferase, and enters the gluconeogenic pathway as Glucose-6-phosphate ABOVE the step that would require fructose bisphosphatase

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20
Q

Why does creatinine clearance slightly overestimate GFR?

A

Creatinine is moderately secreted by PCT

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21
Q

Ulipristal is used for emergency contraception; what is its moa?

A

Competitive inhibitor of progestins at progesterone receptors.

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22
Q

What is a case series study?

A

Study in which researchers present the history and treatment of a small group of similar patients, without describing any sorting into groups or randomization.

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23
Q

Clopidogrel, prasugrel, and ticlopidine moa

A

Inhibit ADP-induced expression of GPIIb/IIIa by irreversibly blocking the ADP (P2Y12) receptor.

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24
Q

Microfilaria, river blindness, firm nontender skin nodules commonly over the iliac crest, knees: what is this? Vector? tx?

A

Onchocerca Volvulus transmitted by the Female Blackfly. Treat rIVER blindness with IVERmectin

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25
Q

Patient has underdeveloped zygomatic bones, mandibular hypoplasia, lower eyelid colobomas (missing tissue), and malformedears. What is this condition and what caused it?

A

This is Treacher Collins Syndrome caused by failure of neural crest cells to migrate into arch 1.

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26
Q

Abciximab, eptifibatide, and tirofiban inhibit what platelet factor directly?

A

GPIIb/IIIa

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27
Q

What does a defect in the LFA-1 integrin (CD18) protein on phagocytes leads to what?

A

Leukocyte adhesion deficiency type 1: impaired migration/chemotaxis. Recurrent skin/ mucosal infections. Absent pus, impaired wound healing, delayed separation of umbilical cord. See a lot of neutrophils in blood because they can’t go to infection sites.

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28
Q

What is the most common place for an african american to get melanoma and what is it called?

A

Acral lentigious; on the palms and soles.

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29
Q

95% confidence interval: .8-1.4

What would p range be?

A

Since confidence interval includes 1, you know it is not significant. P values less than 0.05 indicate significance. Therefore 0.05<p></p>

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30
Q

Precision (reliability) is related to statistical power in what way?

A

Precision (reliability): the consistency and reproducibility of a test. Increased precision leads to increased statistical power (1-beta)

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31
Q

Proliferative glomerulonephritis is also known as?

A

Poststreptococcal glomerulonephritis

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32
Q

MI: SVR, PVR, CO, PCWP***

A

SVR increased
PVR decreased
CO decreased
PCWP increased

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33
Q

MOA of Clomiphene

A

Antagonist at estrogen/testosterone receptors in hypthalamus. Prevents normal feedback inhibition and increases release of LH and FSH.

34
Q

Classic example of a bacteria that uses Conjugation i.e. one[way DNA transfer performed by bacteria carrying a plasmid with the fertility (F) factor

A

E. Coli

35
Q

Mucicarmine stain (red) fungus that is MCC of fungal meningitis, soap bubble lesions, CSF fluid stained w/india ink shows halos

A

Cryptococcus Neoformans

36
Q

Researchers give drug to large group of people w/ the disease to determine “definitely” if the drug works. This step includes a control group, randomization, and blinding

A

Phase III

37
Q

Small cell lung cancer most commonly secretes either ADH or ACTH. If a patient presents with both hypertension and hypokalemia, which one?

A

ACTH: excess ACTH stimulates adrenal cortex to produce cortisol, resulting in cushing’s syndrome. Excess cortisol causes hypertension via potentiation of sympathetic stimulation on the vasculature. ACTH also increases aldosterone which causes hypokalemia

38
Q

Why does a 3-week bed rest after a pelvic fracture (or anything) cause decreased blood volume?

A

If in supine position for a long time you will have increased venous return, leads to increased CO. This negatively feeds back on RAAS. Leading to decreased aldosterone. Therefore, you get increased diuresis which leads to decreased blood and plasma volume

39
Q

Pathogenesis of PNH

A

Complement activity directly against pt’s RBCs. Certain glycolipids are needed on RBC surface to prevent attack from complement, the most notable of which are CD55 and CD59. PNH patients have a PIGA enzyme mutation, which is needed for proper presentation and attachment of CD55/CD59 on RBC surface. So overall, defect in a cell membrane anchor protein

40
Q

What is the origin of CNS neurons, Ependymal cells, Oligodendrocytes, and. Astrocytes?

A

Neuroepithelia in neural tube

41
Q

What is the mutation that leads to familiar amyloid polyneuropathy?

A

Mutated transthyretin (ATTR)

42
Q

What are two well known side effects of the NRTI HIV drugs?

A

HEPATOTOXICITY, and lactic acidosis

43
Q

What are the things that cause a normal anion gap?

A

HARDASS:

Hyperchloremia, Addison disease, Renal tubular acidosis, Diarrhea, Acetazolamide, Spironolactone, Saline infusion

44
Q

What is type II error?

A

Stating that there is not an effect or difference when one actually does exist. Null hypothesis is not rejected when it is in fact false.

45
Q

The cardinal (transverse cervical) ligament connects the cervix to the side wall of the pelvis, what does it contain?

A

Uterine vessels

46
Q

Periorbital edema, muscle tenderness, after eating polar bear meat in northern canada. What is this and how do you diagnose?

A

Muscle biopsy. This is trichenella spirosis

47
Q

Sweating, dilated pupils, piloerection, rhinorrhea, lacrimation, yawning, nausea, stomach cramps, diarrhea

A

Heroin withdrawal (opiates)

48
Q

If someone has their pituitary removed, and semen shows azoospermia and they have poor libido/ can’t maintain erection, then what do you do?

A

Injection of gonadotropins directly (FSH, LH). This is because both are needed to produce sperm.

49
Q

Patient is born, has Respiratory Distress syndrome, is intubated and put on PEEP for a month. After the month, they have persistently increased densities in all lung fields. Lungs are firm and poorly aerated. Microscopic exam shows prominent interstitial fibrosis surrounding irregular, dilated airspaces w/ bronchiolar metaplasia. What is this called.

A

Bronchopulmonary dysplasia

50
Q

MOA of probenecid

A

Inhibits reabsorption of uric acid in proximal convoluted tubule (also inhibits secretion of penicillin)
Probenecid is a sulfa drug

51
Q

Which stage of the cell cycle are MITOTIC cyclins synthesized?

A

G2

52
Q

What would you see in nasal secretions of a patient w/ allergies? Why?

A

Mast cells degranulate, producing histamine which attracts eosinophils. The early stage of an allergic reaction is mast cell mediated, but the late stage (including mucus production)

53
Q

What two species of plasmodium would you see Schuffner stippling in which there is stippling throuhgout the RBC cytoplasm? How would you treat?

A

This would be seen in P Vivax/P Ovale both of which have 48 hour tertian fever (first and third day). Due to these species possibly having hypnozoites you would add primaquine. Make sure to test for G6PD first

54
Q

Traumatic injury to the thorax, pt breathing 22 resp/min, increased tympany to percussion on side of injury=pneumothorax. What are they at risk for?

A

Respiratory acidosis: you have one less lung working, so despite breathing faster might get an increase in CO2.

55
Q

Stent thrombosis vs restenosis

A

Stent thrombosis is more of an acute reaction that often presents with ACS. Restenosis is a gradual narrowing of the stent lumen due to neointimal proliferation

56
Q

How do you calculate Volume of distribution?

A

Vd=amount of drug administered/plasma drug concentration

57
Q

Patient has dysmetria (lack of coordination of intended movements) after getting in crash. Where is lesion?

A

Lateral cerebellum. Could also see dysdiadokinesia and intention tremor w/ a lateral cerebellar defect. If central cerebellum (medial) (vermis) you would see ataxia, wide based gait. Since it is cerebellum, damage on ipsilateral side results in ipsilateral defect ie dysmetria on right is lesion on right lateral cerebellum

58
Q

Patient presents w/ dysphagia, hoarseness, decreased gag reflex, vomiting, vertigo, nystagmus.
They have decreased pain and temp from contralateral body, but IPSIlateral face. They have ipsilateral horner syndrome and ipsilateral ataxia/dysmetria. What is this?

A

Lateral medullary (wallenberg) syndrome. Nucleus ambiguus (CN IX, X, XI) effects are specific to PICA lesions.The PICA also supplies the inferior cerebellar peduncle, hence the ataxia/dysmetria

59
Q

Reproductive aged woman has bloody discharge from the NIP every 28 days. No masses, adenopathy. What is most likely?

A

Intraductal papilloma; it is most common cause of painless bloody discharge from the nip. Benign.

60
Q

What is mutated in early inherited cases of alzheimers?

A

Mutations in presenilin-1/2

61
Q

What is the most common route of toxoplasmosis transmission?

A

Most common route of this parasite is cysts in meat; this is far more common than the oocysts in cat litter

62
Q

What % of data is within 1,2, and 3 standard deviations?

A

68,95,99.7 respectively

63
Q

Patient has vertical gaze palsy due to superior colliculus compression

A

Pineal gland tumor

64
Q

C8 transected, quadraplegic, erection possible how?

A

Reflex involving S2-S4 with direct penile stimulation. Psycogenic erection reflex can’t occur.

65
Q

Patient taking excess of their levothyroxine: what will their Free thyroxine, free triiodothyronine, and Tyroidal Iodine uptake levels be?

A

FT4 and FT3 will be increases; thyroidal iodine uptake is decreased. Levothyroxine is exogenous form of T4, which will be converted to T3 in the peripheral tissues. Both levels up. Less TSH will be made, so you get less thyroid uptake of iodine

66
Q

How does the body respond to blood loss?

-3 points

A

Upregulation of transferrin (iron transporter in the blood), erythropoieitin production (hormone made exclusively in the renal peritubular interstitial cells), and heme synthesis.

67
Q

Pt. Presents w/ severe painful spasms of jaw, abdominal muscles. Loud noise causes painful spasms and eventually pt goes into respiratory failure and needs intubation. Admin of antitoxin prevents further symptoms, but pt needs ventilator support for 3 more weeks. What is the deal

A

Tetanus. Synaptobrevin (SNARE/ soluble NSF attachment protein receptor)is the target of tetanospasmin exotoxin.
Tetanospasmin prevents release of inhibitory (GABA/Glycine) neurotransmitters from Renshaw cells in the spinal cord—> spastic paralysis, risus sardonicus, trismus.

68
Q

Normal appearing female who has 46,XY DSD. Absent or scant axillary/pubic hair. Rudimentary vagina, but no uterus and fallopian tubes.

A

Androgen Insensitivity Syndrome: defect in androgen receptor. Female external genitalia with scant axillary and pubic hair, rudimentary vagina, uterus/tubes absent. Patients develop normal functioning testes often found b/l in labia majora. Causes increases testosterone, estrogen, LH. Increased estrogen because testosterone is converted peripherally leading to female external genitalia.

69
Q

Where does the breakdown of dipeptides and tripeptides to free AA take place?

A

Primarily in the intestinal mucosa

70
Q

Pt with RA is being treated with Infliximab, develops backpain and MRI shows osteomyelitis w/ granuloma formation on biopsy.

A

Tuberculous osteomyelitis because TB can be activated by TNF-alpha inhibitors. TNF plays a significant role in keeping TB in granulomas, when inhibited they can reactivate. Always ppd before starting infliximab.

71
Q

Which NRTI is best known for bone marrow suppression?

A

Zidovudine

72
Q

What is the first step of heme synthesis

A

Condensation of glycine and succinyl CoA into delta-aminolevulinate. This rxn is catalyzed by ALA synthase and is the rate limiting step of heme synthesis.

73
Q

What is the order of DNA—> Protein?

A

DNA is transcribed into hnRNA. Next, Alternative Splicing occurs converting hnRNA into mRNA. Then, the mRNA is translated into proteins. Finally, post-translational modification occurs

74
Q

New born with lethargy, poor feeding, vomiting 48 hours after delivery. Appears flaccid. Serum shows increased concentrations of ammonia and orotic acid. What enzyme is this and what step does it catalyze?

A

Ornithine transcarbamolase: takes ornithine to citruline.

75
Q

Paclitaxel, Vinblastine, Vincristine, Eribulin are all microtubule inhibitors that over stabalize the cancer cell leading to its death. What phase do they work in?

A

M phase.

76
Q

What is the origin of PNS neurons, and Schwann cells?

A

Neural Crest

77
Q

What is the origin of Microglia?

A

Mesoderm

78
Q

ARBs directly block the ANG II receptor (AT1)

What levels would you see regarding renin, ang1, angII, aldosterone, and bradykinin?

A 
Renin: increased
Ang I: increased
Ang II: increased
Aldosterone: decreased
Bradykinin: unchanged
79
Q

Abnormal dihyrorhodamine (flow cytometry) test, showing decreased green fluorescence. Nitroblue tetrazolium dye reduction test fails to turn blue. Susceptible to catalase + organisms. What is this?

A

Chronic granulomatous disease. NADPH oxidase defect

80
Q

How does diabetic ketoacidosis cause both intra and extracellular dehydration?

A

Increase in plasma osmolality dehydrates intracellular compartment. ^plasma osmolality also causes osmotic diuresis, which decreases ECF volume.

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