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USMLE Step 1 Prep

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Depolarization of the postsynaptic membrane...
Ductus epididymis - Which is lined by pseudostratified epithelium with stereocilia.
Areas 44 and 45
Plasmodium vivax
excites the neuron

2. What type of collagen is abnormal in patients with osteogenesis imperfecta?
Parasympathetic stimulation - via the vagus nerve - results in bronchoconstriction - whereas sympathetic stimulation results in bronchodilation.
Type I (makes sense - since they have a predisposition for fractures and type I collagen is associated with bones and tendons)
Carbamazepine
At least 5 lobes

3. What is the term for vitamin D deficiency prior to epiphyseal fusion?
Prolyl and lysyl hydroxylases
Rickets prior to fusion - osteomalacia if the deficiency occurs after epiphyseal fusion.
Temporal arteritis (giant cell arteritis)
Cestodes

4. What is the name of the spinal cord passing within the subarachnoid space and forming the spinal nerves that exit the lumbar and sacral foramina?
Contralateral. The spinothalamic tract enters the spinal cord and immediately synapses in the dorsal horn - crosses over - and ascends contralateral in the spinal cord - brainstem - thalamus - and postcentral gyrus.
Cauda equina
Endometrial cancer
Stage 1

5. What is the most common lethal AR disorder affecting white Americans?
>5 mm
Cystic fibrosis
The JG cells
Wiskott - Aldrich syndrome

6. What is the amount in liters and percent body weight for the following compartments? - ICF
Hepatocellular carcinoma is associated with hepatitis B and C infections - not with EBV.
28 L - 40% of body weight
Arcuate line
Turner syndrome

7. What X- linked recessive immune disorder is characterized by recurrent infections - severe thrombocytopenia - and eczema?
Mumps
Intraductal papilloma
Wiskott - Aldrich syndrome
Measles (rubeola)

8. A 20-year - old woman who was recently diagnosed with a sexually transmitted disease goes to the ER with a tender - painful - swollen - and erythematous knee (monoarticular). What organism is the likely culprit?
Proencephalon
Insulin increases total body stores of protein - fat - and CHOs. When you think insulin - you think storage.
Neisseria gonorrhea (history of STD in patient with monoarticular infectious arthritis: think gonococcus)
Constriction of efferent arteriole

9. What cytoplasmic pathway produces NADPH and is a source of ribose 5- phosphate?
HMP shunt
0157:H7
Sensory
Heterochromatin - the light stuff in the nucleus on an electron microscope image.

10. What artery supplies most of the lateral surfaces of the cerebral hemispheres?
Middle cerebral artery
Prevalence increases. (Incidence does not change.)
Klatskin tumor
Stimulus generalization must stop. (Pairing of the unconditioned stimulus and the conditioned stimulus must cease.)

11. What elongation factor is inactivated by ADP ribosylation - preventing translation?
eEF-2 is the site where Pseudomonas and Diphtheria toxins work.
Five pairs through five lumbar vertebrae. Totaling 31 pairs of spinal nerves.
Alcohol and its related problems cost the country approximately $100 billion a year.
Right - sided valves

12. Name the ocular lesion; be specific - Left Meyer's loop lesion of the optic radiations.
nef and tat genes
At birth (reflex)
Left homonymous hemianopsia
Eclipse period

13. What peripheral chemoreceptor receives the most blood per gram of weight in the body?
Resistance increases as resistors are added to the circuit.
Resistance of the system increases. (Remember - when resistors are connected in a series - the total of the resistance is the sum of the individual resistances.)
The carotid body - which monitors arterial blood directly
LGB (think EYES)

14. All negative sense RNA viruses are...
enveloped
Benign nevus (mole)
Mitral insufficiency
They are inversely related. If ventilation increases - there will be a decrease in PCO2 levels and vice versa.

15. What potentially fatal disease occurs in children who are given aspirin during a viral illness?
Arginine
Prolactin
Cardiac muscle
Reye syndrome

16. At What age do children begin to understand the irreversibility of death?
Contralateral muscle weakness when above the decussation - whereas an UMN injury below the pyramidal decussation results in ipsilateral muscle weakness.
Thymus gland. (Thymus gland is essential for T cell maturation.)
Birds
At 8 to 9 years of age. Prior to this age they view death as a form of punishment.

17. What complement factor or factors are associated with x Chemotaxis?
C5a
HMG CoA reductase
Stapes artery
Schistosoma haematobium

18. What substance do the JG cells of the kidney secrete in response to low blood pressure?
Renin
Coxsackie A
Membrane depolarization is the stimulus to open these slow channels - and if they are prevented from opening - it will slow down the repolarization phase.
Pancreatic insufficiency

19. What is the longest and most convoluted segment of the nephron?
Suprachiasmatic nucleus
Site 4
PCT
Foods rich in tyramine (e.g. - cheese - dried fish - sauerkraut - chocolate - avocados - and red wine) should be avoided. Hypertensive crisis occurs when tyramine and MAOIs are mixed.

20.
Amylase hydrolyzes alpha -1 - 4- glucoside linkages - forming alpha - limit dextrins - maltotriose - and maltose.
Average
Ixodes (also the vector for Lyme disease)
prior to birthThe foramen ovale closes just...

21. What are the three characteristics of autoregulation?
Dantrolene
1. Flow independent of BP 2. Flow proportional to local metabolism 3. Flow independent of nervous reflexes
Paget disease of the breast
Flumazenil

22. What region of the Ig does not change with class switching?
Hypervariable region
Neurofibromatosis
Dystrophic calcification
BPH

23. In a diabetic patient - to What does aldose reductase convert glucose?
Low interstitial free Ca2+ concentrations
Sorbitol (resulting in cataracts)
Vitamin A is responsible for vision and epithelial health.
Erythema marginatum

24. What is the respiratory compensation mechanism for metabolic alkalosis?
The substantia nigra is the largest nucleus in the midbrain. It contains melanin and uses GABA and dopamine as its neurotransmitters.
Vibrio parahaemolyticus
Hypoventilation - which increases CO2 - shifting the reaction to the right and increasing H+
1. Neisseria meningitidis 2. Haemophilus influenzae 3. Streptococcus pneumoniae

25. Paranoid and catatonic schizophrenia are good...
Uracil
prognostic predictors
Hirschsprung disease
Phase 4

26. What Brodmann area is associated with x Wernicke's area?
Area 22 and occasionally 39 and 40
Posterior
Acral - lentiginous melanoma
None; they are not formed until a girl reaches puberty.

27. What phase of Food and Drug Administration approval tests x The protocol and dose levels in a small group of patient volunteers?
Isotonic contraction
Type I hypersensitivity (anaphylactic)
Phase II
Dilation of afferent arteriole

28. A patient goes to the ER with abdominal cramps - vomiting - diarrhea - and sweating less than 24 hours after eating potato salad at a picnic; What is the most likely responsible organism?
Fluconazole
REM sleep. Nightmares are frightening dreams that we recall.
Staphylococcus aureus
Eosin

29. Which direct - acting vasodilator is used clinically to treat hypertensive emergencies - insulinomas - and as a uterine smooth muscle relaxant?
Diazoxide
The lung will expand; also the opposite is true.
Central. Remember - there is a deficiency in ADH production in the central form.
Shortens

30. What cell in the heart has the highest rate of automaticity?
SA node; it is the reason it is the primary pacemaker of the heart.
LCO - an index of lung surface area and membrane thickness - is decreased in fibrosis because of increased membrane thickness and decreased in emphysema because of increased surface area without increase in capillary recruitment; in exercise there is
Negative correlation
Blocking

31. What three criteria allow you to differentiate an ulcer from an erosion or carcinoma?
Bile salts are actively reabsorbed in the distal ileum.
1. Less than 3 cm 2. Clean base 3. Level with the surrounding mucosa
Ganciclovir
Vascular dementia. It is characterized as a stepwise deterioration in cognitive function.

32. What enzyme catalyzes the rate - limiting step in cholesterol metabolism?
Glucose -6- phosphatase
Atrial contraction Atrial - Contraction - Venous
Adulthood
HMG- CoA reductase

33. What are the two essential fatty acids?
C1 inhibitor (C1- INH)
Linoleic acid and linolenic acid
Niemann - Pick and Tay- Sachs diseases
The substantia nigra is the largest nucleus in the midbrain. It contains melanin and uses GABA and dopamine as its neurotransmitters.

34. How does myelination affect conduction velocity of an action potential?
Coronary circulation
Oxygen
Pyloric stenosis
The greater the myelination - the greater the conduction velocity.

35. What type of crystals are associated with gout?
Histiocytosis X
After the eclipse period
CN III - VII - IX - and X
Monosodium urate crystals

36. If the P value is less than or equal to .05 - What do you do to the null hypothesis?
Vmax
Reject it
Ovulation
Voltage - gated sodium channel

37. Which aminoglycoside is used only topically because it is too toxic for systemic use?
Neomycin
ATP/ADP Translocase
Sympathetic nervous system
First - pass effect

38. What is the drug of choice for treating Tourette syndrome?
Pimozide
Gametocytes
The vagina
Zafirlukast

39. What is the most common one? - Site of ulcerative colitis
Adrenarche
Rectum
ACE inhibitors (the - pril agents)
G-6- PD deficiency

40. What embryonic structure forms the adult female structures? - Labia majora
Labioscrotal swelling
Protamine sulfate
Transcortical apraxia; Wernicke's area of the left hemisphere cannot communicate with the right primary motor cortex because of the lesion in the corpus callosum.
1. Low pressure in the afferent renal arteriole 2. Low sodium sensed by the macula densa 3. Increased Beta-1- sympathetic stimulation of the JG cells

41. Protein production - bile secretion - detoxification - conjugation - and lipid storage.
Atelectasis
Functions of hepatocytes
Acanthosis nigricans
Rhombencephalon

42. In a parallel circuit - what happens to resistance when a resistor is added in parallel
Motor
Histidine
Resistance decreases as resistors are added in parallel.
Terbinafine

43. What is the only Rickettsia that is stable in the environment?
Diastole. During systole the left ventricle contracts - resulting in intramyocardial vessel compression and therefore very little blood flow in the coronary circulation.
Coxiella burnetii
Hirschsprung disease
Carnitine acyltransferase - I

44. Which muscarinic receptor uses a decrease in adenyl cyclase as its second messenger?
M 2
Orbitomedial frontal lobe
Lymphoblastic lymphoma
Metaraminol (a1 - Beta1 )

45. Name the most common type or cause - Hematuria
Infection
Prolactin
Necrotizing enterocolitis
Antithyroglobulin and antimicrosomal Abs

46. What cell type is found in the peripheral white pulp of the spleen?
Beta- Oxidation of fatty acids
B cells are mainly found in the peripheral white pulp and germinal centers in the spleen.
Impotence
3 ATPs by oxidative phosphorylation

47. What is the most common one? - Organism associated with mastitis
Staphylococcus aureus
Viruses
The cupola of the lung is posterior to the subclavian artery and vein. It is the reason one must be cautious when performing subclavian venipuncture.
PTH

48. How many ATPs are produced from cytoplasmic NADH oxidation using the malate shuttle?
Inferior pancreaticoduodenal - middle colic - right colic - ileocolic - and 10 to 15 intestinal arteries
Pertussis toxin
Midazolam
3 ATPs by oxidative phosphorylation

49. What is the only pharyngeal muscle not innervated by CN X?
Stages 3 and 4 (NREM)
PDA
Stylopharyngeus muscle is innervated by CN IX; all other pharyngeal muscles are innervated by CN X.
Polycystic ovary disease (Stein - Leventhal syndrome)

50. After fertilization - what cells of the corpus luteum x Secrete estrogen?
DNA polymerases
Theca cells secrete estrogen. After fertilization the theca cells form from the theca interna.
Rhinoviruses for summer and fall; coronaviruses for winter and spring
Intermediate part of the hemispheres