Neuro Block 2 Flashcards
basal nuclei
striatum - caudate and putamen
lentiform nucleus - putamen and globus pallidus
substantia nigra
subthalamic nuclei
hyperkinetic
uncontrolled involuntary movement
Huntingtons
hypokinetic
rigidity, slowness, difficulty initiating movement
Parkinsons
inputs to basal nuclei
cortex to striatum - release Glu
SNc to putamen (nigrostriatal) - release Dopamine
outputs of basal nuclei
GPi to thalamus - motor of body (GABA)
SNr to thalamus - motor of head (GABA)
SNr and GPi to other - superior colliculus, pontomedullary reticular formation (GABA)
Basal nuclei direct pathway
promotes movement
cortex (Glu) to
striatum (GABA) to
SNr and GPi (GABA) to
Thalamus VA/VL (Glu)
Basal nuclei indirect path
inhibits movement
cortex (Glu) to
Striatum (GABA) to
GPe (GABA) to
STN (Glu) to
GPi and SNr (GABA) to
Thalamus VA/VL (Glu)
effects of dopamine
facilitate direct path
inhibit indirect path
so loss will lead to hypokinesia
effect of ACh
facilitate indirect path
increase leads to hypokinesia
sound transduction
- upward movement of basilar membrane pushes endolymph toward top of tectorial membrane
- shifting tectorial membrane deflects stereocilia of outer hair cels depolarizing them (activates prestin which contracts cells)
- enhanced deflection leads to increased endolymph flow and contact of tectorial membrane with iner hair cells
- depolarizaation of inner hair cells releases NTs to stimulate spiral ganglion neurons (cochlear nerve)
- opposite occurs when basilar membrane deflected downward
- efferent signals from superior olivary nucleus modulate effects of outer hair cells
macula
of saccule - cochrlear, connected to spiral organ of corti
of utricle - vestibular, connected to semicircular ducts
otoconia on top (move to stimulate vestibular nerve)
sitting on otolithic membrane
and embedded in otolithic membrane are hair cells
semicircular ducts
in the crista ampularis there are cupula which detect movement of endolymph (hair cells beneath cupula)
otic vesicle development
underneath the tubotympanic recess forms from first pharyngeal pouch
otic placode invaginates to become otic vesicle
vesicle forms endolymphatic sac and duct, utricle dorsally, saccule ventrally
sacule develops into saccule and cochlear duct
spiral organ development
cochlear duct from saccule development uses neuroepithelial cells to form outer hair cells
inside becomes tectoral membrane
inner ridge becomes spiral limbus
spaces form to create spiral tunnels, spiral sulcus
scala tympani and vestibuli development
forming around cochlear duct
originally cartilage which has vacuolization to create the 2 spaces
semicircular ducts development
utricle has outpocketings
vacuolization in middle of outpocketings create the circles
auditory ossicle development
start with mesenchymal condensation
osicles form and embed in loose mesenchyme
mesenchyme erodes leaving ligaments, tympanic cavity, and endodermal epithelium
parkinsons disease
loss of dopaminergic nuclei (substantia nigra and locus ceruleus)
neurons have Lewy bodies
slow movement, pill rolling tremor, loss of facial expression, shuffling gait
Huntington disease
increased CAG repeats (mutation in HTT gene called Huntingtin) - anticipation, less than 36 no disease, 36-39 may develop, over 39 will develop
atrophy/loss of neurons in caudate/putamen
chorea (dancelike mvmt), dementia, psychosis
autosomal dominant (onset late 40)
treat symptoms
multisystem atrophy.striatonigral degeneration
varied degenrations of varied nuclei
glial cytoplasmic inclusions in oligodendroglial cells (alpha synuclein)
-degeneration of substantia nigra and striatum, unresponsive to L-dopa
hemiballismus
wild flinging movements
subthalamic nucleus lesion
Wilsons disease
defeciency of ceruloplasmina nd build up of copper
degeneration of lenticular nucleus
kayser fleischer corneal rings
friederich ataxia (hereditary spinal ataxia)
starts 5-15 yrs
GAA repeats (normal is 7-34, abnormal is more than 90)
often autosomal dominant
loss of neurons in cerebellum, brainstem, spinal cord
ALS
loss upper and lower motor neurons
spastic and flacid paralysis
mutations in CU.Zn superoxide dismutase in familial forms