USMLE STEP 1 Neurology Exam Questions With Correct Answers
5 views 0 purchase
Course
USMLE
Institution
USMLE
USMLE STEP 1 Neurology Exam Questions
With Correct Answers
The notochord induces what to differentiate into what? - answerInduces overlying
ECTODERM to differentiate into NEUROECTODERM and form NUERAL PLATE
Neural plate then gives rise to? - answerNeural tube and neural crest cells
Notochord b...
The Forebrain gives rise to: - answer✔✔1. Telencephalon [Cerebral hemispheres, lateral
ventricles]
2. Diencephalon [Thalamus, Third Ventricle]
The Midbrain gives rise to: - answer✔✔1. Mesencephalon [Midbrain, aqueduct]
The Hindbrain gives rise to: - answer✔✔1. Metencephalon [Pons, cerebellum, upper part of the
fourth ventricle]
2. Myelencephalon [Medulla, Lower part of the fourth ventricle]
Neural tube defects - answer✔✔NEUROPORES fail to fuse [4th week] → Persistent connection
between amniotic cavity and spinal canal
Associated with:
1. Low folate levels before conception and during pregnancy
2. ↑ a-fetoprotein levels [AFP] in amniotic and maternal serum
3. ↑ AChE in amniotic fluid [Helpful confirmatory test]
-- Fetal AChe in CSF transudates across defect into amniotic fluid
Spina bifida occulta - answer✔✔Failure of bony spinal canal to close, NO STRUCTURAL
HERNIATION
Usually seen at lower vertebral levels
DURA INTACT
Associated w/ tuft of hair or skin dimple at level of bony defect
NORMAL AFP
Meningocele - answer✔✔Meninges [BUT NO NEURAL TISSUES] herniates through bony
defect
Meningomyelocele - answer✔✔Meninges and neural tissue herniate through bony defect
Associated w/ Arnold-Chiari Type II Malformation
Anencephaly - answer✔✔Malformation of the ANTERIOR NEURAL TUBE →
1. No forebrain
2. Open calvarium
Clinical Findings:
1. ↑ a-fetoprotein levels [AFP]
2. Polyhydramnios [No swallowing center in brain]
3. Associated w/ MATERNAL TYPE I DIABETES
Holoprosencephaly - answer✔✔Failure of LEFT AND RIGHT HEMISPHERES TO
SEPARATE
Usually occurs during the 5th and 6th week
May be related to mutations in the SONIC HEDGEHOG signaling pathway
Moderate form = Cleft lip/palate
Severe form = Cyclopia
Seen in:
1. PATAU SYNDROME
2. FETAL ALCOHOL SYNDROME
Chiari Type II Malformation - answer✔✔Posterior fossa malformation
Significant HERNIATION of the CEREBELLAR TONSILS and VERMIS through FORAMEN
MAGNUM with AQUEDUCTAL STENOSIS and HYDROCEPHALUS
Patients often present w/:
1. Lumbosacral meningomyelocele
2. Paralysis below the defect
Dandy-Walker Malformation - answer✔✔AGENESIS of CEREBELLAR VERMIS with
CYSTIC ENLARGEMENT of the 4th ventricle
Fills enlarged posterior fossa
Associated w/:
1. Hydrocephalus
2. Spina bifida
Syringomyelia - answer✔✔Cystic cavity [Syrinx] within SPINAL CORD
If central canal = Hydromyelia
Crossing anterior spinal commissural fibers are typically damaged
CAPE-LIKE BILATERAL LOSS OF PAIN and TEMPERATURE in the UPPER
EXTREMITIES
Fine touch sensation is preserved
Associated w/:
Arnold Chiari Type I Malformation - answer✔✔CEREBELLAR TONSILLAR ECTOPIA > 3-5
mm
Congenital
Usually asymptomatic in childhood
Manifests w/ HEADACHE and CEREBELLAR SYMPTOMS
Which arches form the anterior 2/3rds of the tongue - answer✔✔1st and 2nd brachial arches
-- Sensation via CN V
-- Taste via CN VII
Which arches form the posterior 1/3rd of the tongue - answer✔✔3rd and 4th brachial arches
--Sensation and taste via CN IX
-- Extreme posterior vagus
Motor innervation of the tongue - answer✔✔CN XII [Hypoglossal nerve] to:
1. Hyoglossus = Retracts and depresses tongue
2. Genioglossus = Protrudes tongue
3. Styloglossus = Draws sides of tongue upward to create a trough for swallowing
CN X [Vagus] to:
1. Palatoglossus = Elevates posterior tongue during swallowing
Neurons - answer✔✔Signal-transmitting cells of the nervous system
Permanent cells = DO NOT DIVIDE IN ADULTHOOD
Signal relaying cells w/ dendrites [Receive input], cell bodies, and axons [Send output]
CELL BODIES AND DENDRITES CAN BE SEEN ON NISSLE STAINING [Stains RER]
RER is not present in an axon
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Thebright. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.49. You're not tied to anything after your purchase.
