Neuro I - First Aid Flashcards
(219 cards)
The image below depicts the neural tube at about 21 days. Where would you expect most sensory fibers and motor fibers to develop?

During neural development, the alar plate (dorsal) will mostly develop into sensory fibers and the basal plate (ventral) will mostly develop into motor fibers.

What is the role of the notochord during early fetal development? What does this structure actually develop into itself?
Fetal development: induce overlying ectoderm to become neuroectoderm and form the neural plate. Final structure: nucleus pulposus in intervertebral discs.
What will the three primary brain vesicles shown below develop into as pregnancy progresses?

Cerebral hemispheres (telencephalon), thalamus & hypothalamus (diencephalon), midbrain (mesencephalon), pons & cerebellum (metencephalon) and the medulla (myelencephalon)

A mother comes to her OB for her first check up since she had a positive pregnancy test. Routine blood work of maternal serum reveals an elevated alpha-fetoprotein (AFP). What would be the next test you would run?
Test for AFP and AChE in amniotic fluid. Elevated AFP is a marker for neural tube defects. Since there is persistent connection between the amniotic fluid and spinal canal, amniotic AChE levels will be elevated due to leakage from fetal CSF into the amniotic fluid.
A mother comes to her OB for her first check up since she had a positive pregnancy test. Routine blood work of maternal serum reveals an elevated alpha-fetoprotein (AFP). What nutrient might this patient be deficient in?
Folic acid.
Two new babies are born in the labor and deliver department. Physical examination of their skin is shown below. What are possible diagnoses for these conditions?

The top one has spina bifida occulta. The bottom one has a meningocele or a meningomyelocele, further analysis to see if spinal cord is present is necessary to differentiate between the two.

An expecting mother goes to see her OB at 20 weeks. Routine blood work reveals elevated AFP in maternal serum. Ultrasound images are shown below. The doctor tells the expecting mother that in future pregnancies she will need folate supplementation. What condition may be revealed on further examination of her past medical history?

Type I Diabetes. Maternal type I diabetes is associated with anencephaly (failure of the forebrain and superior calavarium to develop)

A 23 year old pregnant woman goes to the ED because of profuse bleeding during the night. She is 22 weeks along and has a confirmed miscarriage. Delivery of the fetus reveals a baby with cleft palate and cyclopia (only one orbit). What forebrain anomaly is associated with these findings?
Holoprosencephaly. During weeks 5-6 the cerebral hemispheres fail to separate. This may be associated with the sonic hedgehog signaling pathway.
While doing rounds in the NICU, the pediatrician checks up on a baby with quadriplegia and a thoracic myelomeningocele. He checks the chart and the diagnosis is Arnold-Chiari II malformation. What anatomic characteristics would he find on examination of this child’s brain MRI?
Cerebellar tonsillar and vermian herniation through foramen magnum, aqueductal stenosis and hydrocephalus.

A mother brings her 8 month old boy to the pediatrician because she noticed his motor skills are not developing and he is way behind the other kids in his play group. Physical examination reveals spina bifida occulta. The boy’s brain CT is shown below. What is your diagnosis?

Dandy-Walker Malformation. This is characterized by a genesis of the cerebellar vermin with an enlarged 4th ventricle. Note that this condition is also associated with spina bifida.

A 22 year old man comes to the primary care clinic complaining of headaches and recent loss of pain and temperature sensation in his back, the back of his arms and hands. Physical exam reveals intact touch and vibratory sensation in these regions. What congenital malformation would you want to check for on this patient’s MRI?
Chiari I malformation. This condition is associated with syringomelia (cystic enlargement of central canal of spinal cord that damages the spinothalamic tract but leaves posterior column in tact)

In what location do you most often find a syrinx in a patient with syringomyelia?
C8-T1

What cells develop from the neuroectoderm?
CNS neurons, ependymal cells, oligodendrocytes & astrocytes. Microglia do not originate from the neuroectoderm, they are derived from the mesoderm.
What cells develop from the neural crest cells?
PNS neurons and Schwann cells
A mother gives birth to a child that is completely paralyzed below the neck. After running blood and imaging studies, there is still no apparent diagnosis. The doctor decides to do a biopsy and stain for neurons. What stain would he use?
Nissl substance. This stains RER, and thus will only stain cell bodies and dendrites because there is not any RER present in the axons.
You are out trimming your lawn. A piece of plastic gets shot toward your elbow and cuts you pretty bad. You lose sensation to your pinky and ring fingers. What histological changes would you see on analysis of the area where the ulnar nerve was cut?
Proximal axonal retraction and distal Wallerian degeneration of the axon.
A 47 year old man presents to the neurologist with recurring headaches and blindness in one eye. MRI reveals a brain tumor. Tumor biopsy reveals cells that are positive for GFAP. What are 6 normal functions carried out by the cells that form this tumor?
GFAP is the astrocyte marker. Normally astrocytes 1) Provide physical support 2) Repair 3) K+ metabolism 4) Remove excess neurotransmitter 5) BBB 6) Reactive gliosis after injury
A 44 year old man comes to the ED with rapidly progressive dementia and encephalopathy. A few days later he dies. History reveals that he had AIDS. What glial cell abnormality would you expect to find in this patient?
Multinucleate giant cells from fused microglia. Microglia do this when they are infected by HIV.

What type of cells look like fried eggs on H&E in patients with multiple sclerosis?

Oligodendrocytes. Multiple sclerosis is a demyelinating disorder and affects these cells that myelinate CNS axons. Note that these will be the most abundant glial cell found in white matter because of abundance of myelinated axons (normal shown below)

A 50 year old man goes to the neurology clinic complaining of rapid-onset ascending paralysis. He is diagnosed with Guillain-Barre syndrome. Why might this patient have greater difficulty healing from a transected nerve during surgery?
Guillain-Barre syndrome attacks the Schwann cells that myelinate PNS axons. These cells are the ones responsible for axonal regeneration after transection.
On histological analysis of a peripheral nerve, how many axons will you likely see around each Schwann cell? What if you were in the CNS.
- Each Schwann cell myelinates only 1 PNS axon. In the CNS, each oligodendrocyte can myelinate up to 50 CNS axons.
What sensory nerve fibers are responsible for sensing pain and temperature?
C-fibers and A-delta fibers
Increased synthesis of what neurotransmitter in what region of the pons will increase anxiety and decrease depression?
NE. Synthesized in the locus ceruleus of the pons. Note that the locus ceruleus is the stress and panic center of the brain.
Increased synthesis of what neurotransmitter in what region of the midbrain will decrease Parkinson’s and decrease depression but increase schizophrenia?
Dopamine. Synthesized in the ventral tegmentum and substantia nigra of the midbrain.
























































































