Neurology Flashcards
Diencephalon gives rise:
Thalamus.
Hypothalamus
Third ventricle
Metencephalon gives rise:
Pons
Cerebellum
Upper part of
fourth ventricle
Telencephalon
Cerebral hemispheres.
Basal ganglia
Lateral ventricles
Normal AFP present in which neural tube defect?
Spina bifida occulta
Holoprosencephaly
Failure of the embryonic forebrain (prosencephalon) to separate into 2 cerebral hemispheres;
during weeks 5- 6
F - fused basal ganglia and ventricles E - Eye (cyclopia) T - trisomy 13 A - alcohol syndrome (fetal) L - lip/palate (cleft)
Lissencephaly
Failure of neuronal migration resulting in a “smooth brain” that lacks sulci and gyro.
May be associated with microcephaly, ventriculomegaly.
Silky
Chiari I malformation
Ectopia of cerebellar tonsils inferior to foramen magnum.
Associated with spinal cavitations (eg, syringomyelia).
Chiari II malformation
Herniation of cerebellar vermis and tonsils through foramen magnum with aqueductal stenosis -> noncommunicating hydrocephalus.
associated with lumbosacral myelomeningocele
Dandy-Walker malformation
Agenesis of cerebellar vermis leads to cystic enlargement of 4th ventricle
Associated with noncommunicating hydrocephalus, spina bifida.
Syringomyelia most common location:
cervical > thoracic» lumbar.
Tongue motor innervation
CN XII:
hyoglossus (retracts and depresses tongue)
genioglossus (protrudes tongue)
styloglossus (draws sides of the tongue upward to create a trough for swallowing).
Motor innervation is via CN X to palatoglossus (elevates posterior tongue during swallowing).
Astrocytes
B - blood-brain barrier
R - repair
a
S - support (physical)
K - K+ buffer i N - neurotransmitter removal G - glycogen fuel reserve G - gliosis (reactive) G - GFAP (astrocyte marker)
Endoneurium
thin, supportive connective tissue that ensheaths and supports individual myelinated nerve fibers.
Perineurium
(blood-nerve Permeability barrier)- surrounds a fascicle of nerve fibers. Must be rejoined in microsurgery for limb reattachment.
Epineurium
dense connective tissue that surrounds entire nerve (fascicles and blood vessels).
Chromatolysis
Characterized by:
• Round cellular swelling
• Displacement of the nucleus to the periphery
• Dispersion of Nissl substance throughout the cytoplasm
Blood-brain barrier
Formed by 3 structures:
Prevents circulating blood substances (eg, bacteria, drugs) from reaching the CSF/ CNS.
Formed by 3 structures:
• Tight junctions between nonfenestrated capillary endothelial cells
• Basement membrane
• Astrocyte foot processes
antagonists used to treat chemotherapy-induced vomiting:
NK-1 antagonists
D2 antagonists
5-HT3 antagonists
all are input to CTZ.
antagonists used to treat motion sickness and hyperemesis gravidarum:
H1 and M1 antagonists
all are input to CTZ.
H1 antagonists treat hyperemesis gravidarum.
circadian rhythm is driven by:
SCN -> norepinephrine release -> pineal gland -> melatonin.
SCN is regulated by the environment (eg, light).
The circadian rhythm controls the nocturnal release of: Prolactin M - melatonin A - ACTH N - norepinephrine
Non-REM sleep - Stage N1
EEG WAVEFORM AND NOTES
(5%) Light sleep.
Theta
Non-REM sleep - Stage N2
EEG WAVEFORM AND NOTES
(45%) Deeper sleep; when bruxism - “twoth” (tooth grinding) occurs.
SeKond - Sleep spindles and K complexes
Non-REM sleep - Stage N3
EEG WAVEFORM AND NOTES
Deepest non-REM sleep. Slow-wave sleep - Delta (lowest frequency, highest amplitude)
sleepwalking, night terrors, and bedwetting occur (wee and flee in N3).
REM sleep - Notes, timing
Loss of motor tone and inc brain O2 use, variable pulse/BP, inc ACh.
REM is when dreaming, nightmares and penile/clitoral tumescence occur; it may serve memory processing function.
Extraocular movements due to the activity of PPRF.
Occurs every 90 minutes, and duration inc through the night.
REM, REM-latency, N3 in depression vs elderly
Changes in elderly: dec REM sleep time, inc REM latency.
Changes in depression: inc REM sleep time, dec REM latency.
Dec N3 in both.
Sleep physiology: NE dec____
N3
Sleep physiology: GABA rec agonist dec____
REM
N3
Preoptic nucleus
Thermoregulation, sexual behavior.
Releases GnRH.
Failure of GnRH- producing neurons to migrate from the olfactory pit - Kallmann syndrome.
INPUT Medial geniculate nucleus
Superior olive and inferior colliculus of the tectum
INPUT to Ventral lateral nucleus
Cerebellum, basal ganglia
Senses motor, goes to Motor cortex.
The limbic system consists of:
H - hippocampus
A - amygdalae
M - mammillary bodies
A - anterior thalamic nuclei
C - cingulate gyrus
E - entorhinal cortex
The limbic system is responsible for:
Feeding, Fleeing, Fighting, Feeling, and Fucking.
Mesocortical pathway:
Dec activity -> “negative” symptoms (eg, anergia, apathy, lack of spontaneity).
Antipsychotic drugs have limited effect.
Mesolimbic pathway:
Inc activity -> “positive” symptoms (eg, delusions, hallucinations).
1° therapeutic target of antipsychotic drugs
Nigrostriatal pathway:
Dec activity - >extrapyramidal symptoms (eg, dystonia, akathisia, parkinsonism, tardive dyskinesia).
Significantly affected by movement disorders and antipsychotic drugs.
Tuberoinfundibular pathway:
Dec activity -> Inc prolactin -> dec libido, sexual dysfunction, galactorrhea, gynecomastia (in men).
CPP is directly proportional to Pco2 until____
Pco2 >90mm Ilg.
Hypoxemia increases CPP only if _____
Po2 < 50 mm Hg.
If CPP = 0?
If CPP = 0, there is no cerebral perfusion -> brain death.
CPP = MAP - ICP.
Therapeutic hyperventilation
-> dec Pco2 -> vasoconstriction -> dec cerebral blood flow -> dec intracranial pressure (ICP).
May be used to treat acute cerebral edema (eg, 2° to stroke)
Cranial nerve nuclei in the spinal cord
Spinal cord-nucleus of CN XI
Middle cranial fossa foramina:
Standing Room Only, Suckers!
Superior orbital fissure
Foramen Rotundum
Foramen Ovale
Foramen spinosum
Posterior cranial fossa foramina:
Includes Jazz, Hip-hop Mofo!
Internal auditory meatus
Jugular foramen
Hypoglossal canal
Foramen magnum
Superior orbital fissure
CN 3,4,6, V1
Foramen Rotundum
CN V2
Foramen Ovale
CN V3
Foramen spinosum
Middle meningeal artery
Internal auditory meatus
CN 7,8
Jugular foramen
CN 9,10,11
jugular vein
Hypoglossal canal
CN 12
Foramen magnum
Brain stem
Spinal root of CN XI
Vertebral arteries
Nucleus Tractus Solitarius
FUNCTION & CRANIAL NERVES
Nucleus - nine
Tractus - ten
Solitarius - seven
Visceral Sensory information (eg, taste, baroreceptors, gut distention)
Nucleus aMbiguus
FUNCTION & CRANIAL NERVES
Motor innervation of pharynx, larynx, upper esophagus (eg, swallowing, palate elevation)
IX, X, XI (cranial portion)
Dorsal motor nucleus
Sends autonomic (parasympathetic) fibers to heart, lungs, upper GI
CN X
Pupillary REFLEX
Gag REFLEX
Pupillary: II -> III
Gag: IX -> X
Mastication muscles
3 muscles close jaw: Masseter, teMporalis, Medial pterygoid.
1 opens: Lateral pterygoid.
All are innervated by trigeminal nerve (V3).