USMLE Step 1 Qs (8)

50 Questions | Total Attempts: 111

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USMLE Step 1 Qs (8) - Quiz

Questions from various sources for practicing


Questions and Answers
  • 1. 
    The proper sensory nucleus is derived from which of the following
    • A. 

      Alar plate

    • B. 

      Basal plate

    • C. 

      Sulcus limitans

    • D. 

      Neural crest

    • E. 

      Roof plate

  • 2. 
    A brain MRI scan taken from a 6-month-old baby revealed that while the overall size of the cerebral cortex was normal, the size of the pyramidal tracts was considerably smaller than normal. Which of the following is the most likely explanation for this defect
    • A. 

      Reduction in the numbers of cortical neurons giving rise to pyramidal tract fibers

    • B. 

      Reduction in the numbers of synaptic contacts made by pyramidal tract neurons

    • C. 

      Reduction in the extent of myelin found on pyramidal tract neurons

    • D. 

      Reduction in the amount of neurotransmitter released by pyramidal tract neurons

    • E. 

      Reduction in the numbers of glial cells attached to pyramidal tract neurons

  • 3. 
    Which of the following is the most ubiquitous excitatory neurotransmitter in the brain?
    • A. 

      ACh

    • B. 

      Glutamate

    • C. 

      Norepinephrine

    • D. 

      Dopamine

    • E. 

      Substance P

  • 4. 
    Epileptiform activity is believed to include the activation of which of the following
    • A. 

      GABA receptors

    • B. 

      Glutamate receptors

    • C. 

      Nicotinic receptors

    • D. 

      Serotonin receptors

    • E. 

      Glycine receptors

  • 5. 
    Which of the following enzymes is directly responsible for the degradation of norepinephrine
    • A. 

      Tryptophan hydroxylase

    • B. 

      Tyrosine hydroxylase

    • C. 

      Dopamine beta-hydroxylase

    • D. 

      Catechol-O-methyltransferase

    • E. 

      Choline acetyltransferase

  • 6. 
    Bladder functions are regulated by which of the following combinations of inputs
    • A. 

      Vagal and sacral efferent fibers only

    • B. 

      Vagal, sacral, and descending fibers from the cerebral cortex

    • C. 

      Lumbar and sacral efferent fibers only

    • D. 

      Lumbar, sacral, and descending fibers from the cerebral cortex

    • E. 

      Lumbar, thoracic, and cervical fibers only

  • 7. 
    Synthesis and storage of norepinephrine can be prevented by which of the following substances
    • A. 

      Guanethidine sulfate

    • B. 

      Reserpine

    • C. 

      Phenoxybenzamine hydrochloride

    • D. 

      Hexamethonium chloride

    • E. 

      Metoprolol

  • 8. 
    A 43-year-old male is recovering from an infectious disease and experiences a marked instability in his blood pressure with episodes of spiking of blood pressure. After a series of extensive examinations, it was concluded that this disorder was due to the effects of the infectious agent upon a component of the peripheral nervous system. Logical sites where an infectious agent could produce such an effect include which of the following
    • A. 

      Superior ganglia of cranial nerves IX and X

    • B. 

      Geniculate and trigeminal ganglia

    • C. 

      Otic and superior salivatory ganglia

    • D. 

      Carotid sinus and aortic arch

    • E. 

      Carotid and aortic bodies

  • 9. 
    The lesion at B would most likely result in which of the following deficits?
    • A. 

      Paralysis of the contralateral limbs

    • B. 

      Loss of conscious proprioception of the contralateral side of the body

    • C. 

      Nystagmus

    • D. 

      Lateral gaze paralysis

    • E. 

      Facial paralysis

  • 10. 
    A patient with the lesion at A will generally show which of the following deficits?
    • A. 

      Partial blindness

    • B. 

      Loss of ability to gaze medially

    • C. 

      Loss of ability to show tracking movements

    • D. 

      Loss of accommodation reflex

    • E. 

      Nystagmus

  • 11. 
    A person is told that he has astigmatism. To correct this defect, the optometrist prescribes which of the following lenses
    • A. 

      Cylindrical lens because the cornea or lens is oblong

    • B. 

      Concave lens because the eyeball is too long

    • C. 

      Convex lens because the lens is too short

    • D. 

      Neutral lens because the eyeball is normal but the cornea is too thin

    • E. 

      Concave lens because the cornea is opaque

  • 12. 
    As a result of calcification of the internal carotid artery, which impinges upon the lateral half of the right optic nerve prior to its entrance to the brain of a 68-year-old woman, resulting in certain visual deficits. Which of the following is the most likely visual deficits
    • A. 

      Total blindness of the right eye

    • B. 

      Right nasal hemianopsia

    • C. 

      Right homonymous hemianopsia

    • D. 

      Right bitemporal hemianopsia

    • E. 

      Right upper homonymous quadrantanopia

  • 13. 
    . A 55-year-old woman complains of headaches and is subsequently diagnosed as having a tumor localized to the left parietal lobe. In addition to a variety of sensory deficits, further examination also reveals a reduction in her visual fields. Which of the following is the most likely visual deficit
    • A. 

      Left homonymous hemianopsia

    • B. 

      Right homonymous hemianopsia

    • C. 

      Left upper quadrantanopia

    • D. 

      Right upper quadrantanopia

    • E. 

      Right lower quadrantanopia

  • 14. 
    . The conscious perception of movement is mediated by which of the following receptors
    • A. 

      Meissner's corpuscles

    • B. 

      Free nerve endings

    • C. 

      Merkel's receptors

    • D. 

      Joint capsules

    • E. 

      Pacinian corpuscles

  • 15. 
    An impairment in the ability to perform certain types of learned, complex movements (referred to as apraxia) usually results from a lesion of which of the following?
    • A. 

      Precentral gyrus

    • B. 

      Postcentral gyrus

    • C. 

      Premotor cortex

    • D. 

      Prefrontal cortex

    • E. 

      Cingulate gyrus

  • 16. 
    Which of the following is the primary transmitter released from terminals of both neostriatal and paleostriatal neurons?
    • A. 

      Glycine

    • B. 

      Enkephalin

    • C. 

      Dopamine

    • D. 

      GABA

    • E. 

      Glutamate

  • 17. 
    The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has recently been applied experimentally with considerable success as a model for which of the following?
    • A. 

      Huntington's disease

    • B. 

      Hemiballism

    • C. 

      Parkinson's disease

    • D. 

      Tardive dyskinesia

    • E. 

      Dystonia

  • 18. 
     A man presents with a wide-based, ataxic gait during his attempts at walking. He also is unsteady and sways when standing and displays a tendency to fall backward or to either side in a drunken manner. A lesion is most likely located in which of the following?
    • A. 

      Hemispheres of the posterior cerebellar lobe

    • B. 

      Anterior limb of the internal capsule

    • C. 

      Dentate nucleus

    • D. 

      Anterior lobe of the cerebellum

    • E. 

      Flocculonodular lobe of the cerebellum

  • 19. 
    . Which one of the following thalamic nuclei makes local connections with other thalamic nuclei and, additionally, projects to the basal ganglia
    • A. 

      Centromedian thalamic nucleus

    • B. 

      Medial geniculate thalamic nucleus

    • C. 

      Lateral geniculate thalamic nucleus

    • D. 

      Dorsomedial thalamic nucleus

    • E. 

      Anterior thalamic nucleus

  • 20. 
    The supraoptic nucleus is most closely associated with which of the following?
    • A. 

      Feeding behavior

    • B. 

      Temperature regulation

    • C. 

      Sexual behavior

    • D. 

      Short-term memory functions

    • E. 

      Water balance

  • 21. 
    Lesions of the lateral hypothalamus will likely produce which of the following
    • A. 

      Feeding behaviors

    • B. 

      Drinking behaviors

    • C. 

      Sexual behaviors

    • D. 

      Aphagia

    • E. 

      Hypertension

  • 22. 
    A number of investigations have provided strong evidence that the suprachiasmatic nucleus plays an important role in which of the following
    • A. 

      Water intake

    • B. 

      Food intake

    • C. 

      Hypertension

    • D. 

      Circadian rhythms

    • E. 

      Short-term memory

  • 23. 
    The CT scan below reveals that the patient has a glioma (T) on the right side of the brain. It is likely that the patient has sustained which of the following?
    • A. 

      A UMN paralysis of the left side

    • B. 

      Dyskinesia

    • C. 

      Intention tremor

    • D. 

      Upper left quadrantanopia

    • E. 

      Upper right quadrantanopia

  • 24. 
    A lesion of which region in the diagram below will likely result in receptive aphasia?
    • A. 

      A

    • B. 

      B

    • C. 

      C

    • D. 

      D

    • E. 

      E

  • 25. 
    A lesion at which site in the figure below will produce a speech deficit, referred to as expressive aphasia?
    • A. 

      C

    • B. 

      D

    • C. 

      E

    • D. 

      F

    • E. 

      G

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