USMLE Step 1 Qs (11)

50 Questions | Total Attempts: 96

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USMLE Step 1 Qs (11) - Quiz

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Questions and Answers
  • 1. 
    . A patient is capable of displaying pupillary constriction during an accommodation reaction but not in response to a direct-light stimulus. The lesion is most likely present in which of the following
    • A. 

      Optic nerve

    • B. 

      Ventral cell column of cranial nerve III

    • C. 

      Pretectal area

    • D. 

      Visual cortex

    • E. 

      Edinger-Westphal nucleus of cranial nerve III

  • 2. 
    Which of the following deficits is likely to occur as a result of the lesion at B?
    • A. 

      Contralateral loss of conscious proprioception

    • B. 

      Transient tremor of the ipsilateral limb

    • C. 

      Ipsilateral fourth-nerve palsy

    • D. 

      Hearing loss

    • E. 

      Contralateral loss of taste sensation

  • 3. 
    The deficits associated with the lesion at C are the result of damage to which of the following?
    • A. 

      Substantia nigra and crus cerebri

    • B. 

      Red nucleus and crus cerebri

    • C. 

      Crus cerebri and cranial nerve III

    • D. 

      Red nucleus and substantia nigra

    • E. 

      Substantia nigra and cranial nerve III

  • 4. 
    Which of the following is the principal ascending auditory pathway of the brainstem?
    • A. 

      Medial lemniscus

    • B. 

      Lateral lemniscus

    • C. 

      Trapezoid body

    • D. 

      Trigeminal lemniscus

    • E. 

      Brachium of the superior colliculus

  • 5. 
    The output of the retina is mediated by which of the following
    • A. 

      Bipolar cells

    • B. 

      Horizontal cells

    • C. 

      Rods

    • D. 

      Cones

    • E. 

      Ganglion cells

  • 6. 
    Which of the following is a direct interneuron linking the receptor and ganglion cells
    • A. 

      Bipolar cell

    • B. 

      Horizontal cell

    • C. 

      Golgi cell

    • D. 

      Amacrine cell

    • E. 

      Optic nerve cell

  • 7. 
    An individual is diagnosed with retinitis pigmentosa, which produces a defective opsin. This defect will most likely result in which of the following
    • A. 

      Degeneration of area 17 of the cerebral cortex

    • B. 

      Degeneration of cone cells

    • C. 

      Loss of central vision

    • D. 

      Total loss of vision

    • E. 

      Reduced response to light

  • 8. 
    A patient complains of having constant headaches involving the frontal region. Further examination reveals increased intraocular pressure. The pupil is dilated but, at the time of examination, there is little evidence of visual deficits. Which of the following is the most likely diagnosis?
    • A. 

      Cataracts

    • B. 

      A tumor of the visual cortex or lateral geniculate nucleus

    • C. 

      A tumor at the base of the brain impinging upon the optic chiasm

    • D. 

      Glaucoma

    • E. 

      Color blindness

  • 9. 
    routine eye examination reveals the presence of inflammation limited to the left optic disk, probably due to neuritis of this region. Which of the following is the most likely visual deficit resulting from this disorder
    • A. 

      Total blindness of the left eye

    • B. 

      Left homonymous hemianopsia

    • C. 

      Left heteronymous hemianopsia

    • D. 

      Left enlargement of the blind spot

    • E. 

      Left upper quadrantanopia

  • 10. 
     A 29-year-old male has a tumor pressing on the base of the brain where it is impinging upon the optic chiasm. He discovers that his field of vision is now seriously affected. Which of the following defects is present in this individual?
    • A. 

      Total blindness of both eyes

    • B. 

      Bitemporal hemianopsia

    • C. 

      Right homonymous hemianopsia

    • D. 

      Binasal hemianopsia

    • E. 

      Right lower homonymous quadrantanopia

  • 11. 
    . A routine magnetic resonance imaging (MRI) reveals the presence of a tumor situated in the left optic tract proximal to the lateral geniculate nucleus. The patient complained of having a reduction in his field of vision. Which of the following is the most likely visual deficit
    • A. 

      Total blindness of the left eye

    • B. 

      Bitemporal hemianopsia

    • C. 

      Right homonymous hemianopsia

    • D. 

      Left homonymous hemianopsia

    • E. 

      Left homonymous quadrantanopia

  • 12. 
    A 70-year-old male is admitted to the emergency room and a subsequent MRI reveals the presence of a tumor involving parts of the left temporal lobe. In addition to certain short-term memory deficits, visual deficits are noted as well. Which of the following is the most likely deficit
    • A. 

      Left homonymous hemianopsia

    • B. 

      Right homonymous hemianopsia

    • C. 

      Left upper quadrantanopia

    • D. 

      Right upper quadrantanopia

    • E. 

      Left lower quadrantanopia

  • 13. 
    Which of the following types of inhibition have been identified within the dorsal column nuclei?
    • A. 

      Feed-forward inhibition utilizing local interneurons only

    • B. 

      Feedback inhibition utilizing local interneurons only

    • C. 

      Distal inhibition from fibers arising in the cerebral cortex only

    • D. 

      Feed-forward, feedback, and distal inhibition

    • E. 

      Feed-forward and distal inhibition only

  • 14. 
    The terminals of different classes of primary nociceptive afferents have been shown to release which of the following transmitters onto dorsal horn neurons of the spinal cord?
    • A. 

      Enkephalins alone

    • B. 

      Glutamate alone

    • C. 

      Substance P alone

    • D. 

      Glutamate and substance P

    • E. 

      Enkephalins, substance P, and glutamate

  • 15. 
    Which of the following regions of the cortex is most closely associated with the conscious perception of smell?
    • A. 

      Temporal neocortex

    • B. 

      Posterior parietal lobule

    • C. 

      Cingulate gyrus

    • D. 

      Prefrontal cortex

    • E. 

      Precentral gyrus

  • 16. 
     Cells that respond to an image in a specific position and have discrete excitatory and inhibitory zones and a specific axis of orientation in which a response occurs are classified as which of the following
    • A. 

      M cells of the lateral geniculate nucleus

    • B. 

      P cells of the lateral geniculate nucleus

    • C. 

      Simple cells of the visual cortex

    • D. 

      Complex cells of the visual cortex

    • E. 

      Hypercomplex cells of the visual cortex

  • 17. 
    The neural basis of olfactory discrimination is believed to utilize which of the following?
    • A. 

      Specific activation of different cell groups within the amygdala

    • B. 

      Specific activation of different groups of olfactory glomeruli that are spatially organized and segregated within the olfactory bulb

    • C. 

      Specific activation of different groups of cells within the olfactory tubercle

    • D. 

      Temporal summation of olfactory signals in the anterior olfactory nucleus

    • E. 

      Temporal summation of olfactory signals in the mediodorsal thalamic nucleus

  • 18. 
    Which of the following sensory systems is able to utilize a circuit that bypasses the thalamus for the transmission of sensory information from the periphery to the cerebral cortex?
    • A. 

      Conscious proprioception

    • B. 

      Taste

    • C. 

      Olfaction

    • D. 

      Vision

    • E. 

      Audition

  • 19. 
    A patient delays initiation of movement, displays an uneven trajectory in moving her hand from above her head to touch her nose, and is uneven in her attempts to demonstrate rapid alternation of pronating and supernating movements of the hand and forearm. Which of the following is the most likely locus of the lesion
    • A. 

      Hemispheres of the posterior cerebellar lobe

    • B. 

      Flocculonodular lobe of the cerebellum

    • C. 

      Vermal region of the anterior cerebellar lobe

    • D. 

      Fastigial nucleus

    • E. 

      Ventral spinocerebellar tract

  • 20. 
     In studying the functional relationships between the motor cortex and the spinal cord, which of the following effects of cortical stimulation on synaptic potentials would an investigator be likely to observe
    • A. 

      The largest potentials would be seen in spinal motor neurons that innervate proximal muscles

    • B. 

      The largest potentials would be seen in spinal motor neurons that innervate distal muscles

    • C. 

      The potentials seen in spinal motor neurons that innervate proximal and distal muscles would be approximately equivalent

    • D. 

      The largest potentials would be seen in spinal sensory neurons that carry information from spindle afferents to the cerebellum

    • E. 

      The largest potentials would be seen in spinal sensory neurons that carry information from proprioceptors to the thalamus

  • 21. 
     Paralysis of the right side of the lower face, right spastic paralysis of the limbs, deviation of the tongue to the right with no atrophy, and no loss of taste from any region of the tongue will likely result from a lesion of which of the following?
    • A. 

      Internal capsule of the right side

    • B. 

      Internal capsule of the left side

    • C. 

      Right pontine tegmentum

    • D. 

      Base of the medulla on the right side

    • E. 

      Base of the medulla on the left side

  • 22. 
    Damage to the subthalamic nucleus will result in which of the following
    • A. 

      Torsion dystonia

    • B. 

      Tremor at rest

    • C. 

      Hemiballism

    • D. 

      Spastic paralysis

    • E. 

      Tardive dyskinesia

  • 23. 
    Which of the following drugs ameliorate choreiform movements?
    • A. 

      ACh blockers because there is an excess of this transmitter in the caudate nucleus

    • B. 

      Dopamine blockers because there is too low a ratio of ACh to dopamine in the neostriatum

    • C. 

      Serotonin blockers because there is too low a ratio of serotonin to ACh and dopamine in the neostriatum

    • D. 

      Substance P antagonists because the ratio of substance P to ACh is too high in the neostriatum

    • E. 

      Norepinephrine antagonists because the ratio of norepinephrine to ACh is too high in the subthalamic nucleus

  • 24. 
    Tardive dyskinesia is most likely the result of which of the following
    • A. 

      A change in serotonin receptors that causes a hypersensitivity to serotonin

    • B. 

      A change in ACh receptors that causes a hypersensitivity to ACh

    • C. 

      A change in enkephalin receptors that causes a hypersensitivity to enkephalin

    • D. 

      A change in dopamine receptors that causes a hypersensitivity to dopamine

    • E. 

      A change in GABA receptors that causes a hypersensitivity to GABA

  • 25. 
    The dorsal spinocerebellar tract, the ventral spinocerebellar tract, and the cuneocerebellar tract, in a general sense, show convergence in their projections to the cerebellum. Which of the following is the principal region within the cerebellum where these fibers converge
    • A. 

      Anterior lobe

    • B. 

      Posterior lobe

    • C. 

      Flocculonodular lobe

    • D. 

      Fastigial nucleus

    • E. 

      Dentate nucleus

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