Neuro UWorld

Question 1

Kinesin?

Answer 1

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

Question 2

Nissl substance = ?

Answer 2

rER in neurons

Question 3

Postulated mechanism for acute opioid tolerance?

Answer 3

Phosphorylation of opioid receptors by protein kinase

Question 4

Postulated mechanism(s) for chronic opioid tolerance?

Answer 4

Increased adenylyl cyclase activity or increased nitric oxide (NO) levels

Question 5

Neurotransmitter shown to interact with opioid pathways to modulate morphine tolerance?

Answer 5

Glutamate

Question 6

Mechanism by which ketamine blocks tolerance development to morphine?

Answer 6

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

Question 7

Glycine function re: glutamate and NMDA receptors?

Answer 7

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

Question 8

Progressively weakening diaphragmatic contractions during maximal voluntary ventilation with intact phrenic nerve stimulation indicates what 2 possible disturbances?

Answer 8

Neuromuscular junction pathology –> Myasthenia gravisAbnormally rapid diaphragmatic muscle fatigue –> Restrictive lung disease, chest wall disease

Question 9

Cellular receptor for cytomegalovirus (CMV)?

Answer 9

Cellular integrins

Question 10

Cellular receptor for Epstein-Barr virus (EBV)?

Answer 10

CD21

Question 11

Cellular receptor for HIV?

Answer 11

CD4 and CXCR4/CCR5

Question 12

Cellular receptor for rabies virus?

Answer 12

Nicotinic ACh receptor

Question 13

Cellular receptor for rhinovirus?

Answer 13

ICAM-1 = CD54

Question 14

Agitation, disorientation, pharyngospasn, and photophobia leading to coma and death?

Answer 14

Rabies encephalitisPharyngeal muscle spasm cause dysphagia, which can lead to avoidance of food and water (hydrophobia)

Question 15

Rabies virus is a single-stranded RNA virus enveloped by a capsule with what unique shape?

Answer 15

Bullet-shaped capsule, which is studded by glycoprotein spikes that bind to nicotinic AChRs

Question 16

Mechanism by which rabies virus travels to CNS?

Answer 16

Bind AChRs on peripheral nerve axons and travel via retrograde transport to CNS

Question 17

Post-exposure prophylaxis for rabies virus is no longer effective when?

Answer 17

Symptoms of rabies encephalitis appear

Question 18

Improper fusion of maxillary prominence with medial nasal prominence?

Answer 18

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

Question 19

Improper fusion of palatine shelves, or improper fusion of palatine shelf with intermaxillary segment (primary palate)

Answer 19

Cleft palate

Question 20

Intracranial calcified cystic mass filled with thick brownish fluid that is rich in cholesterol?

Answer 20

Craniopharyngioma

Question 21

White pupillary reflex is indicative of?

Answer 21

Retinoblastoma

Question 22

Sporadic retinoblastoma:Associated malignancy?Unilateral/bilateral?

Answer 22

Associated malignancy –> None! Children with sporadic retinoblastoma are not at risk for other malignancies Sporadic retinoblastoma is usually unilateral

Question 23

Familial retinoblastoma:Associated malignancy?Unilateral/bilateral?

Answer 23

Associated malignancy –> OsteosarcomaFamilial retinoblastoma is usually bilateral

Question 24

Familial retinoblastoma: Gene?Chromosome?

Answer 24

Gene –> Rb tumor suppressor geneChromosome 13

Question 25

Rb tumor suppressor gene function?

Answer 25

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

Question 26

Characteristic abnormality seen in patients with Huntington disease?

Answer 26

Bilateral atrophy of caudate nucleus and putamen (striatum)

Question 27

Most characteristic biochemical feature in patients with Huntington disease?

Answer 27

Caudate atrophy --> Loss of GABA-containing neurons

Question 28

Neurotransmitter thought to participate in formation of new memories?

Answer 28

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

Question 29

Involuntary perioral movements such as biting, chewing, grimacing, and tongue protrusions

Answer 29

Tardive dyskinesia

Question 30

Atypical antipsychotic least likely to cause tardive dyskinesia?

Answer 30

Clozapine

Question 31

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?

Answer 31

Clozapine is a/w agranulocytosis

Question 32

Subjective feeling of restlessness that compels patient to constantly move around?

Answer 32

Akathisia

Question 33

Triad of Wernicke syndrome?

Answer 33

Oculomotor dysfunction, ataxia, and confusion

Question 34

Oculomotor dysfunction in Wernicke syndrome is 2/2 damage involving what 3 structures?

Answer 34

CN III, CN VI, and vestibular nuclei

Question 35

Ataxia in Wernicke syndrome is 2/2 damage involving what 2 structures?

Answer 35

Cerebellar cortex and vestibular nuclei

Question 36

Triad of Korsakoff syndrome?

Answer 36

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

Question 37

Korsakoff syndrome is a/w damage to what 2 structures?

Answer 37

Anterior and dorsomedial thalamic nuclei

Question 38

S/p administering thiamine to patient with Wernicke syndrome, what symptom is most likely to persist permanently?

Answer 38

Memory impairment is permanent

Question 39

Werknicke-Korsakoff is a/w lesions that commonly involve what brain structure?

Answer 39

Mammillary bodies

Question 40

Most common clinical manifestation of primary HSV-1 infection in child aged 1-3 years?

Answer 40

Acute gingivostomatitis --> Swollen gums with ulcerative lesions. Oral lesion scrapings demonstrate cells with intranuclear inclusions.