HY Questions Flashcards
What proteins compose gap junctions that form electrical synapses between neurons?
- Connexons.
What second messenger is involved with all norepinephrine receptors?
- cAMP.
What enzyme is responsible for the degradation of cAMP?
- Phosphodiesterase.
Which muscle spindle afferent fibers transmit information about muscle contraction velocity?
- Ia afferent fibers.
What is the response of Golgi tendon organs to muscle contraction?
- Marked increase in firing rate.
What ion is primarily responsible for resting membrane potential in neurons and glia?
- Potassium.
Where are the cell bodies of olfactory neurons located?
- Olfactory epithelium.
What is the MOA of Baclofen?
- GABA-B agonist.
What is the only sensory modality to bypass the thalamus?
- Smell.
What enzyme generates diacylglycerol?
- Phospholipase C.
What causes the miniature end-plate potential?
- The spontaneous release of one quanta of ACh.
What is the mechanism of action of tricyclic antidepressants?
- They block reuptake of NE and 5-HT.
What is responsible for the BBB?
- Tight junctions between endothelial cells.
Which circumventricular organ has an intact BBB?
- The subcommissural organ.
What ion is responsible for the initial depolarization of cochlear hair cells?
- Potassium.
What obstructs the NMDA channel pore at resting membrane potential?
- Magnesium.
What initiates contraction in smooth muscle?
- Calcium-calmodulin activation of myosin light chain kinase.
What is the rate limiting enzyme in dopamine synthesis?
- Tyrosine hydroxlyase.
What is the function of myelin?
- It increases transmembrane resistance and decreases membrane capacitance.
What drug blocks voltage-gated Na channels?
- Tetrodotoxin.
What is the function of the macula of the utricle?
- Detect linear acceleration in the horizontal plane.
What is the shape of the receptive fields of primary visual cortex neurons?
- Rectangular.
Fibers from the ipsilateral retina synapse in which layers of the lateral geniculate body?
- 2, 3, and 5.
What nerve fibers mediate the sensation of sharp pain?
- A-delta.
What protein mediates fast anterograde axonal transport?
- Kinesin.
What is the primary target of dentate nucleus efferent fibers?
- VL nucleus of the thalamus.
What are the most excitatory fibers of the CNS?
- Climbing fibers.
What is the neurotransmitter of the Renshaw cell?
- Glycine.
What type of receptors are present on the Renshaw cell?
- Muscarinic cholinergic receptors.
How do you differentiate a femoral neuropathy from a lumbar plexopathy?
- Hip adduction will be preserved in the former and absent in the latter.
What is the only output of the cerebellar cortex?
- The Purkinje cell.
What nerve is compressed in the tarsal tunnel?
- Posterior tibial nerve.
What structure contains the highest levels of substance P in the brain?
- The substantia nigra.
What structures are connected by the stria medullary thalami?
- The septal nuclei and the habenular nuclei.
What cranial nerve contains the nodosal ganglion?
- The vagus nerve.
Where do SVA fibers synapse in the brainstem?
- The nucleus of the solitary tract (gustatory nucleus).
Where do the frontopontine fibers travel in the internal capsule?
- The anterior limb.
What nerve is compressed by Struther’s ligament?
- The median nerve.
Where is the posterior interosseus nerve often entrapted?
- At the supinator (arcade of Frohse).
Where do GVA fibers traveling in Hering’s nerve synapse?
- The inferior aspect of the solitary tract.
When does the posterior neuropore close?
- Post-ovulatory day 26.
Where do first-order sympathetic neurons to the pupillary dilator originate?
- The hypothalamus.
Where is the cortical area for macular vision located?
- Occipital poles.
Where is the first site of binaural convergence in the auditory pathway?
- The superior olives.
What structures pass through the annulus of Zinn?
- CN II, III, VI, the ophthalmic artery and the nasociliary nerve.
Where do preganglionic parasympathetic fibers destined for the lacrimal glands synapse?
- The pterygopalatine ganglion.
What innervates the cricothyroid?
- The superior laryngeal nerve (of CN X).
What fibers travel in the juxtarestiform body?
- Vestibulocerebellars and cerebellovestibulars.
What region of primary somesthetic cortex do muscle spindles project?
- 3a.
What artery perfuses the retrolenticular internal capsule?
- The anterior choroidal artery.
What is the 5-year stroke risk of asymptomatic 80% carotid artery stenosis?
- 16.5% (3.3% per year x 5 years).
What gene is responsible for Duchenne muscular dystrophy?
- Dystrophin (Xp21).
What cranial nerve is most commonly involved in neurosarcoidosis?
- CN VII.
What is the most common cause of aseptic (viral) meningitis?
- Enteroviruses.
What lesions result in downbeat nystagmus?
- Lesions of the cervicomedullary junction.
What intestinal disease is associated with a hypercoagulable state?
- Ulcerative colitis.
What is the most common cause of occult spinal dysraphism?
- Spinal lipoma.
Maternal hyperglycemia is a risk factor for which spinal developmental disorder?
- Caudal regression syndrome.
Trisomy 13 or 18 is associated with what developmental anomaly of the brain?
- Holoprosencephaly.
What neurodegenerative disorder is associated with pre- and postcentral gyrus atrophy and focal arm dystonia?
- Corticobasal degeneration.
What chromosome is abnormal in Huntington’s disease?
- Chromosome 4.
What gene is abnormal in spinobulbar muscular atrophy (Kennedy’s disease)?
- The androgen receptor gene (X chromosome).
What neurocutaneous syndrome is associated with sphenoid dysplasia and optic gliomas?
- NF-1.
What is the inheritance pattern of Sturge-Weber syndrome?
- Sporadic.
What neurocutaneous syndrome often presents with epistaxis?
- Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease).
What HLA allele is associated with multiple sclerosis?
- DR2.
What abnormal compound accumulates in patients with metachromatic leukodystrophy?
- Sulfatide.
What GI tract infection is associated with the development of Guillain-Barre syndrome?
- Campylobacter jejuni infections.
What stage of sleep is associated with night terrors?
- Stages 3 and 4 (deep sleep).
What disorders are associated with incremental responses on repetitive nerve stimulation studies?
- Presynaptic disorders of the neuromuscular junction (Lambert-Eaton syndrome and botulism).
What are the EEG findings of infantile spasms (West syndrome)?
- Hypsarrythmia.
What is the most common pathogen associated with cerebral abscesses?
- Streptococcus milleri.
What is the treatment of choice for toxoplasmosis in AIDS patients?
- Pyrimethamine and sulfadiazine.
What arterial occlusion results in alexia without agraphia?
- Dominant PCA.
What arterial occlusion is classically associated with lateral medullary infarction (Wallenberg’s syndrome)?
- PICA.
What tumor exhibits desmosomes and is vimentin positive?
- Meningioma.
What intracranial tumor is associated with polycythemia?
- Hemangioblastoma.
What is the inheritance pattern of familial cavernomas?
- Autosomal dominant.
What differentiates pituitary hyperplasia from a pituitary adenoma?
- The presence of reticulin with pituitary hyperplasia.
What is the composition of the Lewy body?
- Ubiquitin, alpha synuclein, alphaB crystallin, and neurofilaments.
What chromosome is abnormal in Huntington’s disease?
- Chromosome 4.
What enzyme is deficient in Gaucher’s disease?
- Glucocerebrosidase.
What is the most common isolate from cerebral abscesses?
- Streptococcus milleri.
What leukodystrophy involves the subcortical U fibers and results from deficiencies of the enzyme aspartoacylase?
- Canavan’s disease.
What allele is commonly associated with multiple sclerosis?
- HLA DR2.
What type of closed head injury often affects the splenium of the corpus callosum?
- DAI.
What cranial nerve is most commonly involved with neurosarcoidosis?
- CN VII.
What type of CNS tumor is associated with syncytiotrophoblasts?
- Choriocarcinoma.
What type of CNS tumor exhibits “stag horn” vasculature?
- Hemangiopericytoma.
What is the most common chromosomal abnormality in meningiomas?
- Monosomy 22.
What CNS tumor is often associated with prominent granulomatous inflammation?
- Germinoma.
What is the most common chromosomal abnormality in GBM?
- Gains of chromosome 7 or 20.
What is the most common molecular abnormality in GBM?
- Allelic loss of 10p and 10q.
What disorder exhibits ballooned neurons and atrophy of the pre- and postcentral gyri?
- Corticobasal degeneration.
What is the appearance of an acute intracerebral hematoma on T2WI?
- Markedly hypointense to surrounding brain.
What is the most common location of a spinal meningioma?
- Thoracic spine.
What is the most common location of choroid plexus papillomas in children?
- 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?
- Epidermoid.
What is the most common location for spinal cellular ependymomas?
- Intramedullary in the cervical spinal cord.
What is the most common chromosomal abnormality in meningiomas?
- Monosomy 22.
What intramedullary spinal cord tumor is associated with NF-2?
- Ependymoma.
What is the only non-enhancing intraventricular tumor?
- Subependymoma.
What is the mechanism of injury in Hangman’s fractures?
- Hyperextension.
What blood vessel is most commonly responsible for compression of the trigeminal nerve with trigeminal neuralgia?
- Superior cerebellar artery.
What is the method activity of BCNU?
- DNA alkylating agent.
What is the primary contraindication to the surgical treatment of Parkinson’s disease?
- No significant response to prior medical therapy with L-dopa.
What is the treatment of choice for chronic, intractable brachial plexus avulsion pain?
- DREZ lesioning.
What is the most common mechanism of injury in patients with odontoid fractures?
- Hyperflexion injuries.
What type of spinal AVM consists of a dural AV fistula and often presents with chronic neurological deterioration secondary to venous hypertension?
- Type 1.
What is the surgical treatment of choice in children with frequent atonic seizures that are refractory to medical therapies?
- Corpus callosotomy.
What basal cisterns contain portions of the basal vein of Rosenthal?
- The ambient and crural cisterns.
What structure separates the facial nerve from the superior vestibular nerve?
- Bill’s bar.
What structure separates the chiasmatic cistern from the interpeduncular cistern?
- Liliequist’s membrane.
What cranial nerve palsy is associated with Gradenigo’s syndrome?
- 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?
- Hyperemia.
What is unique about distal anterior cerebral artery aneurysms?
- They commonly result from trauma against the falx or are mycotic in nature.
What is the annual hemorrhage risk of intracranial AVMs?
- 3-4 %.
Where is the mosts common intracranial location for dural AV fistulas?
- Along the transverse sinus.
What feature of dural AV fistula necessitates treatment?
- The presence of retrograde cortical venous drainage.
What is the inheritance pattern for familial cavernomas?
- Autosomal dominant.
What cranial nerves are susceptible to injury during carotid endarterectomy?
- The hypoglossal nerve and the marginal mandibular branch of the facial nerve.
What familial syndrome is associated with pituitary adenomas?
- Multiple endocrine neoplasia type 1.
What is the most common pineal region tumor in children?
- Germinoma.
What is the most common pattern of hearing loss in patients with acoustic neuromas?
- High frequency sensorineural hearing loss.
What level is most commonly involved with degenerative isthmic spondylolisthesis?
- L4-5.
What approach is associated with the highest morbidity in the treatment of thoracic disc herniations?
- Dorsal laminectomy.
What condition results in prominent lymphocyte casts on urinalysis?
- Acute interstitial nephritis.
What EKG findings are associated with hyperkalemia?
- Peaked T waves and a prolonged PR interval and QRS duration.
What is the treatment of choice for arsenic poisoning?
- BAL.
What inhalational anesthetic is associated with a decreased seizure threshold?
- Enflurane.
What blood product should be used in the treatment of coagulopathy associated with von Willebrand’s disease?
- Cryoprecipitate.
What disorder exhibits prominent epithelial cell casts on urinalysis?
- Acute tubular necrosis.
What is the most sensitive method of diagnosing an intraoperative venous air embolus?
- Transesophageal echo.
What position is ideal to minimize complications from a venous air embolism?
- Left lateral decubitus.
What barbiturate lowers seizure threshold?
- Methohexital.