HY Questions Flashcards
<p>What ion is primarily responsible for resting membrane potential in neurons and glia?</p>
<p>1. Potassium.</p>
<p>What is the MOA of Baclofen?</p>
<p>1. GABA-B agonist.</p>
<p>What causes the miniature end-plate potential?</p>
<p>1. The spontaneous release of one quanta of ACh.</p>
<p>What is the mechanism of action of tricyclic antidepressants?</p>
<p>1. They block reuptake of NE and 5-HT.</p>
<p>What is responsible for the BBB?</p>
<p>1. Tight junctions between endothelial cells.</p>
<p>Which circumventricular organ has an intact BBB?</p>
<p>1. The subcommissural organ.</p>
<p>What ion is responsible for the initial depolarization of cochlear hair cells?</p>
<p>1. Potassium.</p>
<p>What obstructs the NMDA channel pore at resting membrane potential?</p>
<p>1. Magnesium.</p>
<p>What initiates contraction in smooth muscle?</p>
<p>1. Calcium-calmodulin activation of myosin light chain kinase.</p>
<p>What is the rate limiting enzyme in dopamine synthesis?</p>
<p>1. Tyrosine hydroxlyase.</p>
<p>What is the function of myelin?</p>
<p>1. It increases transmembrane resistance and decreases membrane capacitance.</p>
<p>What drug blocks voltage-gated Na channels?</p>
<p>1. Tetrodotoxin.</p>
<p>What nerve fibers mediate the sensation of sharp pain?</p>
<p>1. A-delta.</p>
<p>What protein mediates fast anterograde axonal transport?</p>
<p>1. Kinesin. </p>
<p>What is the primary target of dentate nucleus efferent fibers?</p>
<p>1. VL nucleus of the thalamus.</p>
<p>What are the most excitatory fibers of the CNS?</p>
<p>1. Climbing fibers.</p>
<p>How do you differentiate a femoral neuropathy from a lumbar plexopathy?</p>
<p>1. Hip adduction will be preserved in the former and absent in the latter.</p>
<p>What is the only output of the cerebellar cortex?</p>
<p>1. The Purkinje cell.</p>
<p>What nerve is compressed in the tarsal tunnel?</p>
<p>1. Posterior tibial nerve.</p>
<p>What structure contains the highest levels of substance P in the brain?</p>
<p>1. The substantia nigra.</p>
<p>What structures are connected by the stria medullary thalami?</p>
<p>1. The septal nuclei and the habenular nuclei.</p>
<p>What cranial nerve contains the nodosal ganglion?</p>
<p>1. The vagus nerve.</p>
<p>Where do SVA fibers synapse in the brainstem?</p>
<p>1. The nucleus of the solitary tract (gustatory nucleus).</p>
<p>Where do the frontopontine fibers travel in the internal capsule?</p>
<p>1. The anterior limb.</p>
What nerve is compressed by Struther's ligament?
1. The median nerve.
Where is the posterior interosseus nerve often entrapted?
1. At the supinator (arcade of Frohse).
Where do GVA fibers traveling in Hering's nerve synapse?
1. The inferior aspect of the solitary tract.
When does the posterior neuropore close?
1. Post-ovulatory day 26.
Where do first-order sympathetic neurons to the pupillary dilator originate?
1. The hypothalamus.
Where is the cortical area for macular vision located?
1. Occipital poles.
Where is the first site of binaural convergence in the auditory pathway?
1. The superior olives.
Where do preganglionic parasympathetic fibers destined for the lacrimal glands synapse?
1. The pterygopalatine ganglion.
What region of primary somesthetic cortex do muscle spindles project?
1. 3a.
What artery perfuses the retrolenticular internal capsule?
1. The anterior choroidal artery.
What is the 5-year stroke risk of asymptomatic 80% carotid artery stenosis?
1. 16.5% (3.3% per year x 5 years).
What gene is responsible for Duchenne muscular dystrophy?
1. Dystrophin (Xp21).
What cranial nerve is most commonly involved in neurosarcoidosis?
1. CN VII.
What is the most common cause of aseptic (viral) meningitis?
1. Enteroviruses.
What lesions result in downbeat nystagmus?
1. Lesions of the cervicomedullary junction.
Maternal hyperglycemia is a risk factor for which spinal developmental disorder?
1. Caudal regression syndrome.
Trisomy 13 or 18 is associated with what developmental anomaly of the brain?
1. Holoprosencephaly.
What neurodegenerative disorder is associated with pre- and postcentral gyrus atrophy and focal arm dystonia?
1. Corticobasal degeneration.
What chromosome is abnormal in Huntington's disease?
1. Chromosome 4.
What gene is abnormal in spinobulbar muscular atrophy (Kennedy's disease)?
1. The androgen receptor gene (X chromosome).
What neurocutaneous syndrome is associated with sphenoid dysplasia and optic gliomas?
1. NF-1.
What is the inheritance pattern of Sturge-Weber syndrome?
1. Sporadic.
What neurocutaneous syndrome often presents with epistaxis?
1. Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease).
What HLA allele is associated with multiple sclerosis?
1. DR2.
What abnormal compound accumulates in patients with metachromatic leukodystrophy?
1. Sulfatide.
What GI tract infection is associated with the development of Guillain-Barre syndrome?
1. Campylobacter jejuni infections.
What stage of sleep is associated with night terrors?
1. Stages 3 and 4 (deep sleep).
What disorders are associated with incremental responses on repetitive nerve stimulation studies?
1. Presynaptic disorders of the neuromuscular junction (Lambert-Eaton syndrome and botulism).
What is the most common pathogen associated with cerebral abscesses?
1. Streptococcus milleri.
What is the treatment of choice for toxoplasmosis in AIDS patients?
1. Pyrimethamine and sulfadiazine.
What arterial occlusion results in alexia without agraphia?
1. Dominant PCA.
What arterial occlusion is classically associated with lateral medullary infarction (Wallenberg's syndrome)?
1. PICA.
What tumor exhibits desmosomes and is vimentin positive?
1. Meningioma.
What intracranial tumor is associated with polycythemia?
1. Hemangioblastoma.
What is the inheritance pattern of familial cavernomas?
1. Autosomal dominant.
What differentiates pituitary hyperplasia from a pituitary adenoma?
1. The presence of reticulin with pituitary hyperplasia.
What is the composition of the Lewy body?
1. Ubiquitin, alpha synuclein, alphaB crystallin, and neurofilaments.
What chromosome is abnormal in Huntington's disease?
1. Chromosome 4.
What enzyme is deficient in Gaucher's disease?
1. Glucocerebrosidase.
What is the most common isolate from cerebral abscesses?
1. Streptococcus milleri.
What leukodystrophy involves the subcortical U fibers and results from deficiencies of the enzyme aspartoacylase?
1. Canavan's disease.
What allele is commonly associated with multiple sclerosis?
1. HLA DR2.
What type of closed head injury often affects the splenium of the corpus callosum?
1. DAI.
What cranial nerve is most commonly involved with neurosarcoidosis?
1. CN VII.
What type of CNS tumor is associated with syncytiotrophoblasts?
1. Choriocarcinoma.
What type of CNS tumor exhibits "stag horn" vasculature?
1. Hemangiopericytoma.
What is the most common chromosomal abnormality in meningiomas?
1. Monosomy 22.
What CNS tumor is often associated with prominent granulomatous inflammation?
1. Germinoma.
What is the most common chromosomal abnormality in GBM?
1. Gains of chromosome 7 or 20.
What is the most common molecular abnormality in GBM?
1. Allelic loss of 10p and 10q.
What disorder exhibits ballooned neurons and atrophy of the pre- and postcentral gyri?
1. Corticobasal degeneration.
What is the appearance of an acute intracerebral hematoma on T2WI?
1. Markedly hypointense to surrounding brain.
What is the most common location of a spinal meningioma?
1. Thoracic spine.
What is the most common location of choroid plexus papillomas in children?
1. The lateral ventricles.
What tumor has signal characteristics that are similar to CSF on T1 and T2 but also often exhibits increased signal on DWI?
1. Epidermoid.
What is the most common location for spinal cellular ependymomas?
1. Intramedullary in the cervical spinal cord.
What is the most common chromosomal abnormality in meningiomas?
1. Monosomy 22.
What intramedullary spinal cord tumor is associated with NF-2?
1. Ependymoma.
What is the only non-enhancing intraventricular tumor?
1. Subependymoma.
What is the mechanism of injury in Hangman's fractures?
1. Hyperextension.
What blood vessel is most commonly responsible for compression of the trigeminal nerve with trigeminal neuralgia?
1. Superior cerebellar artery.
What is the primary contraindication to the surgical treatment of Parkinson's disease?
1. No significant response to prior medical therapy with L-dopa.
What is the surgical treatment of choice in children with frequent atonic seizures that are refractory to medical therapies?
1. Corpus callosotomy.
What basal cisterns contain portions of the basal vein of Rosenthal?
1. The ambient and crural cisterns.
What cranial nerve palsy is associated with Gradenigo's syndrome?
1. CN VI.
What is the most common cause of malignant cerebral edema within 24 hours of the initial closed head injury in the pediatric population?
1. Hyperemia.
What is unique about distal anterior cerebral artery aneurysms?
1. They commonly result from trauma against the falx or are mycotic in nature.
What is the annual hemorrhage risk of intracranial AVMs?
1. 3-4 %.
Where is the mosts common intracranial location for dural AV fistulas?
1. Along the transverse sinus.
What feature of dural AV fistula necessitates treatment?
1. The presence of retrograde cortical venous drainage.
What is the inheritance pattern for familial cavernomas?
1. Autosomal dominant.
What cranial nerves are susceptible to injury during carotid endarterectomy?
1. The hypoglossal nerve and the marginal mandibular branch of the facial nerve.
What familial syndrome is associated with pituitary adenomas?
1. Multiple endocrine neoplasia type 1.
What is the most common pineal region tumor in children?
1. Germinoma.
What is the most common pattern of hearing loss in patients with acoustic neuromas?
1. High frequency sensorineural hearing loss.
What inhalational anesthetic is associated with a decreased seizure threshold?
1. Enflurane.
What blood product should be used in the treatment of coagulopathy associated with von Willebrand's disease?
1. Cryoprecipitate.
