Neuroscience Flashcards
Dsyfunction of Broca vs. Wernicke areas (dominant hemisphere)
Dysfunction of Broca’s area → expressive/motor aphasia characterized by slow speech consisting primarily of nouns and verbs (agrammatism) and preserved speech comprehension; patients are often frustrated because they are aware of their problem
Dysfunction of Wernicke’s area → receptive/sensory aphasia characterized by impaired comprehension and fluent aphasia (speech flows readily but is meaningless); patients often lack insight into their problem
Embryonic derivation of microglia cells?
Mesoderm
Embryonic derivation of CNS vs. PNS structures
CNS neurons, ependymal cells, oligodendroglia, and astrocytes → neuroectoderm
PNS neurons, Schwann cells → neural crest
Embryologic derivation of optic nerve and tract
Neural ectoderm → diencephalon
What bones are formed from pharyngeal arch I?
Maxilla
Part of temporal bone
Mandible
Malleus
Incus
Sphenomandibular ligament
What bones are formed from pharyngeal arch II?
Upper part of hyoid
Stapes
Styloid
Stylohyoid ligament
What bones are formed from pharyngeal arch III?
Rest of hyoid
What bones are formed from pharyngeal arch IV and VI?
Laryngeal cartilages
What muscles are formed from pharyngeal arch I?
Muscles of mastication
Mylohyoid
Anterior belly of digastric
Tensor tympani
Tensor veli palatini
What muscles are formed from pharyngeal arch II?
Muscles of facial expression
Stapedius
Stylohyoid
Posterior belly of digastric
What muscles are formed from pharyngeal arch III?
Stylopharyngeus
What muscles are formed from pharyngeal arch IV?
Pharyngeal constrictors
Salpingopharyngeus
Palatopharyngeus
Levator veli palatini
Palatoglossus
Cricothyroid
What muscles are formed from pharyngeal arch VI?
Remaining laryngeals (except cricothyroid)
Which nerve innervates pharyngeal arch I?
CN V3 (mandibular nerve)
Which nerve innervates pharyngeal arch II?
CN VII (facial nerve)
Which nerve innervates pharyngeal arch III?
CN IX (glossopharyngeal nerve)
Which nerve innervates pharyngeal arch IV?
CN X (vagus nerve)
Which nerve innervates pharyngeal arch VI?
CN X (recurrent laryngeal nerve of vagus nerve)
Pharyngeal pouches
1st → auditory tube
2nd → tonsillar crypt
3rd → inferior parathyroids, thymus
4th → superior parathyroids, C cells of thyroid
Innervation of the tongue
Anterior tongue → V3 (sensation), VII (taste)
Middle tongue → IX (sensation and taste)
Posterior tongue → X (sensation and taste)
Motor → XII
Acoustic neuroma
Benign proliferation of Schwann cells
Typically located in internal acoutic meatus (CN VIII)
If bilateral, strongly associated with neurofibromatosis type 2
Oligodendrocytes vs. Schwann cells
Oligodendrocytes → myelinates multiple axons in the CNS; degeneration causes MS, PML, leukodystrophies
Schwann cells → myelineates one axon in the periphery; denegeneration causes Guillain-Barre
Epidural vs. subdural hematoma
Epidural hematoma → biconvex blood collection that doesn’t cross suture lines, rupture of middle meningeal artery
Subdural hematoma → crescent-shaped hemorrhage that crosses suture lines, midline shifts, rupture of bridging veins
Normal pressure hydrocephalus
Decreased CSF absorption by arachnoid granulations → communicating hydrocephalus
Imaging: ventriculomegaly out of proportion to or without corresponsding sulci enlargement
Triad: urinary incontinence (stretching of descending cortical fibers → decreased inhibitory control of bladder contractions), ataxia, cognitive dysfunction (“wet, wobbly, and whacky”)
Tx: removal of CSF
Where to place the needle for lumbar puncture?
Between L3 and L5
(“To keep the cord alive, keep the spinal needle between L3 and L5”)
Lower vs. upper motor neuron lesions
Lower motor neuron lesions
Flaccid paralysis
Fasciculations
Reduced muscle tone
Reduced myotatic reflex
Rapid atrophy
Upper motor neuron lesions
Spastic paralysis
Increased muscle tone
Exaggerated myotatic reflex
Increased resistance to passive stretch
Babinski sign
Slow atrophy
Poliomyelitis
Lesions in spinal anterior horns → ipsilateral lower motor neuron signs
Similar features seen in spinal muscular atrophy (Werdnig-Hoffman disease) → “floppy baby” with hypotonia and tongue fasciculations
What causes spinal anterior horn lesions?
Poliomyelitis
West Nile
Spinal muscular atrophy
Amyotrophic lateral sclerosis
ALS AKA Lou Gehrig disease is caused by a defect in superoxide dismutase I
Riluzole modestly increases survival by decreasing presynaptic glutamate release
Lesions in lateral corticospinal tract and anterior horns → combined UMN and LMN signs → fasiculations with eventual atrophy and weakness of the hands
What cranial nerves traverse the cavenous sinus?
CN III
CN IV
CN VI
CN V1
CN V2
What goes through the optic canal?
CN II (optic nerve) Ophthalmic artery
What goes through the superior orbital fissure?
CN III (occulomotor nerve)
CN IV (trochlear nerve)
CN V1 (ophthalmic nerve)
CN VI (abducens nerve)
Ophthalmic vein
What goes through the foramen rotundum?
CN V2 (maxillary nerve)
What goes through the foramen ovale?
CN V3 (mandibular nerve)
What goes through the foramen spinosum?
Middle meningeal artery Meningeal nerve (V3)
What goes through the internal acoustic meatus?
CN VII (facial nerve)
CN VIII (vestibulocochlear nerve)
What goes through the jugular foramen?
CN IX (glossopharyngeal nerve)
CN X (vagus nerve)
CN XI (spinal accessory nerve) exits
Inferior petrosal sinus
Jugular bulb
What goes through the hypoglossal canal?
CN XII (hypoglossal nerve)
What goes through the foramen magnum?
Brain stem/spinal cord junction
CN XI (spinal accessory nerve) enters
Vertebral arteries