Neurology Flashcards
What induces the ectoderm to differentiate into neuroectoderm and neural plate?
Notochord
What gives rise to the neural plate?
Neuroectoderm and neural crest cells
What is the fate of notochord?
nucleus pulpous of the intervertebral disc
What are neural crest derivatives?
Sensory ganglia of cranial and spinal nerves Neurolemmal sheath of PNS Meninges Retinal pigment cells Cells of adrenal medulla
Failure of neuronal migration resulting in a “smooth brain” that lacks sulci and gyri
Lissencephaly
Congenital failure of the cerebellar vermis to develop causing massively dilated 4th ventricle, absent cerebellum, hydrocephalus
Dandy-Walker Malformation
Differentiate Chiari I malformation from Chiari II malformation
Chiari I - ectopia of cerebellar TONSILS into foramen magnum –> headaches, cerebellar s/sx, associated with syringomyelia
Chiari II - ectopia of TONSILS and VERMIS into foramen magnum with aqueductal stenosis–> non-communicating hydrocephalus, associated with lumbosacral myelomeningocele
Chiari I = 1 structure
Chiari II = 2 structures
Cystic cavity (syrinx) within central canal of spinal cord. What is this condition usually associated with?
Syringomyelia and is usually associated with Chiari I malformation
What part of the spinal cord is damaged first in syringomyelia?
Fibers crossing in anterior white commissure (spinothalamic tract) causing “cape-like (C5-T4)” bilateral, symmetrical loss of pain and temperature sensation in upper extremities. Fine touch is preserved
What pharyngeal arch does the tongue develop from?
Anterior 2/3 = 1st and 2nd pharyngeal arch
Posterior 1/3 = 3rd and 4th pharyngeal arch
What are the sensory innervations of the tongue?
Anterior 2/3
Sensation - V3
Taste - VII
Posterior 1/3
Sensation - IX
extreme posterior - X
What are the motor innervations of the tongue?
X - palatoglossus –> elevates posterior tongue during deglutition
XII:
Hyoglossus –> retracts and depresses tongue
Genioglossus –> protrudes tongue
Styloglossus –> draws sides of tongue upward to create a trough for swallowing
This is the most common glial cell type in CNS, neuroectodermal. Provides physical support, repair, extracellular K buffer, removal of excess neurotransmitter, component of BBB, glycogen fuel reserve, and reactive in response to neuronal injury
Astrocytes
These are phagocytic scavenger cells of CNS, mesodermal in origin. Activation of these cells release inflammatory mediators
Microglia
What are multinucleated giant cells seen in HIV-associated dementia?
fused microglia
These are ciliated simple columnar glial cells that line the ventricles and central canal of spinal cord
Ependymal cells
Specialized ependymal cells that produce CSF
Choroid plexus
What are characteristics of chromatolysis?
Round cellular swelling
displacement of nucleus to periphery
dispersion of Nissl substance throughout the cytoplasm
This is disintegration of the axon and myelin sheath distal to the site of axonal injury with microglial cells (macrophages) removing the debris
Wallerian-Degeneration
Neurotransmitter location of synthesis
ACh - basal nucleus of Maynert Dopamine - ventral tegmentum, substantia nigra GABA - nucleus accumbens NE - locus ceruleus (pons) 5HT - Raphe nucluei (pons, medulla)
Where is chemoreceptor trigger zone located?
area postrema in 4th ventricle
Chemoreceptor trigger zone and adjacent vomiting center receive input from which receptors?
M1 H1 D2 5-HT3 NK-1 (Neurokinin)
Classify antiemetics based on receptors
5HT3, D2, NK-1 antagonists treat chemotherapy induced vomiting
H1 and M1 antagonists treat motion sickness, H1 antagonists for hyperemesis gravidarum
Hypothalamic nucleus that is responsible for hunger. Stimulated by ghrelin and inhibited by leptin
Lateral nucleus
Hypothalamic nucleus responsible for satiety. Stimulated by Leptin and inhibited by ghrelin
Ventro-medial nucleus
Hypothalamic nucleus for cooling and parasympathetic
Anterior nucleus
A/C = anterior cooling
Hypothalamic nucleus for heating and sympathetic
Posterior nucleus
Hot Pot
Hypothalamic nucleus for circadian rhythm,
Suprachiasmatic nucleus (SCN)
SCN - Sun Sensing Nucleus
Hypothalamic nucleus that synthesizes ADH and oxytocin
Supraoptic and Paraventricular nucleus
SAD POX = Supraoptic - ADH, Paraventricular - Oxytocin
Hypothalamic nucleus for thermoregulations sexual behavior, and releases GnRH
Preoptic nucleus