Neuro UWorld Flashcards
Kinesin?
Microtubule-associated, ATP-powered motor protein that facilitates anterograde transport of intracellular vesicles and organelles toward plus (rapidly growing) ends of microtubulesNeurons: Kinesin transports neurotransmitter-containing secretory vesicles away from cell body, down axons, toward synaptic nerve terminals
Nissl substance = ?
rER in neurons
Postulated mechanism for acute opioid tolerance?
Phosphorylation of opioid receptors by protein kinase
Postulated mechanism(s) for chronic opioid tolerance?
Increased adenylyl cyclase activity or increased nitric oxide (NO) levels
Neurotransmitter shown to interact with opioid pathways to modulate morphine tolerance?
Glutamate
Mechanism by which ketamine blocks tolerance development to morphine?
Glutamate is an excitatory neurotransmitter that binds and activates NMDA receptorsNMDA receptor activation –> Increased phosphorylation of opioid receptors and increased NO levels –> opioid toleranceKetamine = NMDA receptor antagonist –> Blocks action of glutamate on NMDA receptor and effectively blocks morphine tolerance
Glycine function re: glutamate and NMDA receptors?
Glycine is a co-agonist for glutamate and is required for binding of glutamate to NMDA receptorsBinding of both glycine and glutamate is necessary for NMDA receptor activation
Progressively weakening diaphragmatic contractions during maximal voluntary ventilation with intact phrenic nerve stimulation indicates what 2 possible disturbances?
Neuromuscular junction pathology –> Myasthenia gravisAbnormally rapid diaphragmatic muscle fatigue –> Restrictive lung disease, chest wall disease
Cellular receptor for cytomegalovirus (CMV)?
Cellular integrins
Cellular receptor for Epstein-Barr virus (EBV)?
CD21
Cellular receptor for HIV?
CD4 and CXCR4/CCR5
Cellular receptor for rabies virus?
Nicotinic ACh receptor
Cellular receptor for rhinovirus?
ICAM-1 = CD54
Agitation, disorientation, pharyngospasn, and photophobia leading to coma and death?
Rabies encephalitisPharyngeal muscle spasm cause dysphagia, which can lead to avoidance of food and water (hydrophobia)
Rabies virus is a single-stranded RNA virus enveloped by a capsule with what unique shape?
Bullet-shaped capsule, which is studded by glycoprotein spikes that bind to nicotinic AChRs
Mechanism by which rabies virus travels to CNS?
Bind AChRs on peripheral nerve axons and travel via retrograde transport to CNS
Post-exposure prophylaxis for rabies virus is no longer effective when?
Symptoms of rabies encephalitis appear
Improper fusion of maxillary prominence with medial nasal prominence?
Cleft lip1) Fusion of 2 medial nasal prominences to form midline intermaxillary segment2) Left and right maxillary prominences fuse with midline intermaxillary segment to form upper lip
Improper fusion of palatine shelves, or improper fusion of palatine shelf with intermaxillary segment (primary palate)
Cleft palate
Intracranial calcified cystic mass filled with thick brownish fluid that is rich in cholesterol?
Craniopharyngioma
White pupillary reflex is indicative of?
Retinoblastoma
Sporadic retinoblastoma:Associated malignancy?Unilateral/bilateral?
Associated malignancy –> None! Children with sporadic retinoblastoma are not at risk for other malignancies Sporadic retinoblastoma is usually unilateral
Familial retinoblastoma:Associated malignancy?Unilateral/bilateral?
Associated malignancy –> OsteosarcomaFamilial retinoblastoma is usually bilateral
Familial retinoblastoma: Gene?Chromosome?
Gene –> Rb tumor suppressor geneChromosome 13
Rb tumor suppressor gene function?
Rb protein –> Active and inactive statesActive (dephosphorylated) Rb protein does not allow cell to proceed from G1 to S stage of cell cycle When cell is stimulated by a growth factor, Rb protein is converted to inactive state (phosphorylated), which permits cell divisionCells with 2 inactive Rb genes divide uncontrollably and give rise to malignancy
Characteristic abnormality seen in patients with Huntington disease?
Bilateral atrophy of caudate nucleus and putamen (striatum)
Most characteristic biochemical feature in patients with Huntington disease?
Caudate atrophy –> Loss of GABA-containing neurons
Neurotransmitter thought to participate in formation of new memories?
Nitric oxide NO is a unique neurotransmitter in that it freely diffuses across cell membranes and does not need to interact with other neurons via a synapse
Involuntary perioral movements such as biting, chewing, grimacing, and tongue protrusions
Tardive dyskinesia
Atypical antipsychotic least likely to cause tardive dyskinesia?
Clozapine
Tardive dyskinesia is best managed by decreasing dose of offending antipsychotic OR discontinuing offending antipsychotic and replacing with clozapine. Why is clozapine a medication of last resort?
Clozapine is a/w agranulocytosis
Subjective feeling of restlessness that compels patient to constantly move around?
Akathisia
Triad of Wernicke syndrome?
Oculomotor dysfunction, ataxia, and confusion
Oculomotor dysfunction in Wernicke syndrome is 2/2 damage involving what 3 structures?
CN III, CN VI, and vestibular nuclei
Ataxia in Wernicke syndrome is 2/2 damage involving what 2 structures?
Cerebellar cortex and vestibular nuclei
Triad of Korsakoff syndrome?
Memory loss, confabulation, anterograde amnesia Confabulation = When unsure of a fact, patient fills in memory gap with fabricated story he/she believes to be trueAnterograde amnesia = Inability to form new memories Korsakoff syndrome = Complication of Wernicke syndrome
Korsakoff syndrome is a/w damage to what 2 structures?
Anterior and dorsomedial thalamic nuclei
S/p administering thiamine to patient with Wernicke syndrome, what symptom is most likely to persist permanently?
Memory impairment is permanent
Werknicke-Korsakoff is a/w lesions that commonly involve what brain structure?
Mammillary bodies
Most common clinical manifestation of primary HSV-1 infection in child aged 1-3 years?
Acute gingivostomatitis –> Swollen gums with ulcerative lesions. Oral lesion scrapings demonstrate cells with intranuclear inclusions.
