Neurology Flashcards
What is the role of the notochord?
Induces overlying ectoderm to differentiate into neuroectoderm and form neural plate.
What is the role of the neural plate?
Gives rise to neural tube and neural crest cells.
What does the notochord become?
Nucleus pulposus of the intervertebral discs
What does the neural tube become?
Spinal cord and brain
What are the three primary vesicles and 5 secondary vesicles of the developing brain?
Prosencephalon (forebrain; becomes diencephalon and 2 telencephalons), Mesencephalon (midbrain), Rhombencephalon (hindbrain; becomes metencephalon and myelencephalon)
What does the neuroectoderm differentiate into?
CNS neurons, ependymal cells, oligodendroglia, astrocytes
What do the neural crest cells differentiate into?
PNS neurons, Schwann cells
In what week of gestation do neural tube defects occur?
4th week
What is an Arnold-Chiari malformation and what is another name for it?
Chiari malformation II; Herniation of cerebellar tonsils and vermis through foramen magnum with aqueductal stenosis and hydrocephalus. Often with lumbosacral myelomeningocele and paralysis below defect.
What is a Dandy-Walker malformation?
Agenesis of cerebellar vermis with cystic enlargement of 4th ventricle. Associated with hydrocephalus and spina bifida.
What is the role of microglia?
CNS phagocytes. HIV-infected microglia fuse to form multinucleated giant cells in CNS
Multiple sclerosis, progressive multifocal leukoencephalopathy (PML), and leukodystrophies are all a result of what?
Injured oligodendroglia (myelination in CNS)
Guillain-Barré is a result of what?
Destruction of Schwann cells; ascending paralysis
Where is NE synthesized?
Locus ceruleus (pons)
Where is DA synthesized?
Ventral tegmentum and SNc (midbrain)
Where is 5-HT synthesized?
Raphe nucleus (pons, medulla, midbrain)
Where is ACh synthesized?
Basal nucleus of Meynert
Where is GABA synthesized?
Nucleus accumbens
The BBB is formed by which 3 structures?
Tight junctions between non-fenestrated capillary endothelial cells, basement membrane, and astrocyte foot processes
What specifically makes ADH?
Supraoptic nucleus of the hypothalamus
What specifically makes oxytocin?
Paraventricular nucleus
The lateral area of the hypothalamus is responsible for what? What happens in its destruction? What is the lateral area inhibited by?
Hunger; Anorexia, failure to thrive; Leptin
The ventromedial area of the hypothalamus is responsible for what? What happens in its destruction? What is the ventromedial area stimulated by?
Satiety; Hyperphagia; Leptin
The anterior hypothalamus is responsible for what?
Cooling, parasympathetic. “A/C: Anterior Cooling”
The posterior hypothalamus is responsible for what?
Heating, sympathetic.
The suprachiasmatic nucleus of the hypothalamus is responsible for what?
Circadian rythm
Branchial clefts are derived from which embryonic layer?
Ectoderm
Branchial arches are derived from which embryonic layer?
Mesoderm
Branchial pouches are derived from which embryonic layer?
Endoderm
What does the 1st cleft develop into?
External auditory meatus
What do the 2nd-4th clefts form?
Temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme.
What does a persistent cervical sinus lead to?
Branchial cleft cyst within lateral neck.
How is bedwetting (sleep enuresis) treated?
Oral desmopressin acetate (DDAVP) which mimics ADH
How are night terrors and sleepwalking treated?
Benzodiazepines
What is the input to the VPL nucleus of the thalamus?
Spinothalamic and dorsal columns/medial lemniscus
What is the input to the VPM nucleus of the thalamus?
Trigeminal and gustatory pathway
What is the input to the LGN nucleus of the thalamus?
CNII (vision)
What is the input to the MGN nucleus of the thalamus?
Superior olive and inferior colliculus of tectum (hearing)
What is the input to the VL nucleus of the thalamus?
Basal ganglia, cerebellum (motor)
Which structures make up the limbic system? What is the limbic system responsible for?
Hippocampus, amygdala, fornix, mammillary bodies, and cingulate gyrus. The famous 5 F’s: Feeding, Fleeing, Fighting, Feeling, and Fucking
What is an intention tremor?
Slow, zig zag motion when pointing/extending toward a target - cerebellar dysfunction
What is hemiballismus?
Sudden, wild flailing of 1 arm +/- ipsilateral leg - contralateral subthalamic nucleus (lacunar stroke)
What is athetosis?
Slow, writhing movements; especially seen in fingers - basal ganglia (Huntington)
What is myoclonus?
Sudden, brief, uncontrolled muscle contraction
What is Kluver-Bucy syndrome?
Bilateral lesion of amygdala. Hyperorality, hypersexuality, disinhibited behavior. Associated with HSV-1.
What are the consequences of a right parietal-temporal cortex lesion?
Spatial neglect syndrome (agnosia of the contralateral side of world)
What are the consequences of a left parietal-temporal cortex lesion?
Agraphia, acalculia, finger agnosia, and L-R disorientation. Aka Gerstmann syndrome.
What are the consequences of a lesion to the subthalamic nucleus?
Contralateral hemiballismus
What are the consequences of a lesion to the paramedian pontine reticular formation?
Eyes look away from side of lesion
What are the consequences of a lesion to the frontal eye fields?
Eyes look toward lesion
What disease process results from correcting serum Na too fast?
Central pontine myelinolysis
What is central pontine myelinolysis?
A variant of the osmotic demyelination syndrome. Acute paralysis, dysarthria, dysphagia, diplopia, and loss of consciousness. “Locked-in syndrome.”
What is conduction aphasia?
Poor repetition but fluent speech, intact comprehension
What is transcortical motor aphasia?
Nonfluent aphasia with good comprehension and repetition
What is transcortical sensory aphasia?
Poor comprehension with fluent speech and repetition
What is mixed transcortical aphasia?
Nonfluent speech, poor comprehension, good repetition
What is the most common location of a berry aneurysm?
Junction of anterior communicating artery and anterior cerebral artery
Which diseases are berry aneurysms associated with?
ADPKD, Ehlers-Danlos, and Marfan syndrome
What is a Charcot-Bouchard microaneurysm?
Associated with chronic HTN, affects small vessels (basal ganglia, thalamus)
An epidural hematoma is most commonly caused by rupture of which artery?
Middle meningeal artery
Does an epidural hematoma cross suture lines? Fax and tentorium?
Does not cross suture lines; can cross falx and tentorium
Does a subdural hematoma cross suture lines? Fax and tentorium?
Crosses suture lines; cannot cross falx or tentorium
A subdural hematoma is most commonly caused by rupture of what?
Rupture of bridging veins of arachnoid space
Which type of intracranial hemorrhage causes bloody or yellow (xanthochromatic) spinal tap?
Subarachnoid hemorrhage
Which disease process causes one to be “wet wobbly and wacky?”
Normal pressure hydrocephalus
How many spinal nerves do we have?
- 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 cocygeal
What are the common sites of a vertebral disc herniation?
Posterolaterally at L4-L5 or L5-S1
Where is a lumbar puncture performed?
Between L3 and L5 (cauda equina)
What are characteristics of an UMN lesion?
Spastic paralysis, Babinski +, weakness, hyperreflexia, more tone, clasp knife spasticity
What are characteristics of an LMN lesion?
Weakness, atrophy, hyporeflexia, fasciculations, low tone, flaccid paralysis
What medication can modestly increase survival of ALS patients?
Riluzole - decreases presynaptic glutamate release
A complete occlusion of the anterior spinal artery would spare which portion of the spinal cord?
The dorsal columns and Lissauer tracts
What is Tabes dorsalis?
Degeneration/demyelination of dorsal columns and roots, caused by tertiary syphilis. Exam will demonstrate Argyll Robertson pupils, Charcot joints, shooting pain, absence of DTRs, and positive Romberg.
What are Argyll Robertson pupils?
Small bilateral pupils that further constrict to accommodation and convergence, but not to light. Seen in Tabes dorsalis.
What is a positive Romberg sign?
Pt stands up with feet together and can only keep balance with their eyes open.
A VitaminB12 or VitE deficiency will affect which portions of the spinal cord?
Dorsal column, lateral corticospinal tracts, and spinocerebellar tracts.
What is Werdnig-Hoffman disease?
Congenital degeneration of anterior horns of spinal cord –> LMN lesion. Floppy baby with marked hypotonia and tongue fasciculations. Mutations in the survival motor neuron (SMN1) gene - involved in assembly of snRNPs (spliceosome).
What is the inheritance pattern of Freidreich ataxia?
Autosomal recessive
What is the inheritance pattern of Werdnig-Hoffman disease?
Autosomal recessive
Mutations in the survival motor neuron (SMN1) gene are associated with what disease?
Werdnig-Hoffman disease
Freidreich ataxia is do to what molecular process?
Trinucleotide repeat disorder (GAA) on chromosome 9 in gene that encodes frataxin (iron binding protein). Leads to impairment of mitochondrial functioning.
What are the clinical findings of Freidreich ataxia?
Muscle weakness, loss of DTRs, vibratory sense, proprioception. Staggering gait, falls, nystagmus, dysarthria, pes cavus, hammer toes, hypertrophic cardiomyopathy (cause of death).
How does Freidreich ataxia present in childhood?
Kyphoscoliosis
What is Brown-Séquard syndrome and what are its findings?
Hemisection of spinal cord. Ipsilateral UMN signs below level of lesion, ipsilateral LMN at level of lesion, ipsilateral loss of tactile, vibration, proprioreception sense 1-2 levels below level of lesion, contralateral pain and temperature loss below level of lesion.
What is the landmark of dermatome C2?
Posterior half of a skull “cap”
What is the landmark of dermatome C3?
High turtleneck shirt
What is the landmark of dermatome C4?
Low collared shirt
What is the landmark of dermatome T4?
Nipple
What is the landmark of dermatome T7?
Xiphoid process
What is the landmark of dermatome T10?
Belly button
What is the landmark of dermatome L1?
Inguinal ligament
What is the landmark of dermatome L4?
Kneecaps
What is the landmark of dermatome S2, S3, S4?
Erection and sensation of penile and anal zones
The biceps reflex is associated with which nerve root?
C5
The triceps reflex is associated with which nerve root?
C7
The patellar reflex is associated with which nerve root?
L4
The achilles reflex is associated with which nerve root?
S1
Primitive reflexes are inhibited by what in neurologically intact adults?
Mature/developing frontal lobe
What is the moro reflex?
“Hang on for life” reflex - abduct/extend limbs when startled, then draw together
What is the rooting reflex?
Movement of head toward one side if cheek or mouth is stroked
What is the sucking reflex?
Sucking response when roof of mouth is touched
What is the palmar reflex?
Holding on to finger