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98 Cards in this Set

  • Front
  • Back
how do you correct myopia?
with a concave lens
pathway of aqueous humor
produced by ciliary epithelium, flows into anterior chamber and out through trabecular meshwork and canal of Schlemm
cell layers of the eye
photoreceptors (rods and cones)
horizontal cell
bipolar cell
amacrine cell
ganglion cell
more sensitive to scattered light; for night vision; lower acuity
rods
less photopigment; day vision; most sensitive to direct axial rays; high acuity
cones
what determines whether ganglion cells is "on-center" vs. "off-center"
type of glutamate receptor that is expressed
what type of ganglion cell projections mediate the pupillary reflex?
W type
where do P type ganglion cells project and what type of info do they carry?
to layers 3-6
info about color vision
where do M type ganglion cells project and what type of info do they carry?
to layers 1-2
infor about movement
6 neocortical layers from outside to inside
molecular layer
external granular layer
external puramidal layer
internal granular layer
internal pyramidal layer
fusiform layer
which layer of neocortex is primary recipeient of thalamocortical inputs?
layer IV
which layer of neocortex is main source of projections to thalamus from cortex?
layer VI
what type of visual info does dorsal pathway carry and where does it go?
motion
depth perception
relative size
parietal lobe
what type of visual info does ventral pathway carry and where does it go?
object/form recognition
temporal lobe
what does vestibulooccular reflex do?
keep eyes fixed on a target when the head is moving
what makes endolymph and what is special about it?
stria vascularis
K+ rich
lateral and medial vestibulospinal tract
adjust head position and tone of body with movement of head
righting reflexes
tonic neck reflexes
reticular formation
for ANS responses to vestibular stimulation
ventral posteroinferior nucleus and ventral posterolateral nucleus
projects to postcentral gyrus for conscious perception of movement
MLF
links medial moving eye to lateral one
attenuation reflex
tensor tympani and stapedium muscle stiffen ossicles in response to loud sounds
inner hair cells
afferents
outer hair cells
efferents from superior olivary complex
exhibit electromotility
dorsal cochlear nuclei
info about frequency
ventral cochlear nuclei
info about sound localization--go to sup. olivary nuclei and cross to both sides
where is auditory space map made?
inferior colliculus
filiform
no taste receptors
fungiform
throughout tongue
foliate
along back of tongue along edges
vallate
back of tongue--have about 1/2 of tast receptors
what does pineal produce?
melatonin
epithalamus
pineal gland and habenular nuclei
purpose of epithalamus
way for limbic structures and olfactory stimuli to affect brainstem reticular formation (behavior)
what results from damage to subthalamus
hemiballism
what thalamic nucleus does not project to the cerebral cortex?
reticular thalamic nucleus
tonic mode
slight depolarization results in discharge; hyperpolarization results in inhibition--transmits patterned info accurately
burst mode
no transmission of specific info
slight depolarization opens special voltage gated calcium channels
three types of thalamic nuclei
relay nuclei
association nuclei
nonspecific nuclei
fxn of relay nuclei
receive well defined input and project to functionally distinct areas of cortex
fxn of association nuclei
most input from cerebral cortex and project to association areas of cerebral cortex--maintain normal level of cortical activity and may regulate communication between cortical areas
fxn of nonspecific nuclei
receive input from midbrain reticular formation, project widely in cerebral cortex
ascending reticular activating system
damage can result in coma
ascending reticular activating system
see activity in midbrain when drowsy, but acitivity in thalamus when alert
what separates the thalamus into regions?
internal medullary lamina
input to ventral posterolateral nucleus
medial lemniscus
spinothalamic
input to ventral posteromedial nucleus
trigeminothalamic-->projects to primary somatosensory area in postcentral gyrus
fxn of ventral tier of lateral region of thalamus
somatosensory
ventral lateral nucleus
inputs: cerebellar afferents (dentate) and basal gangia
projects to primary motor area of precentral gyrus al to premotor area
fxn of ventral lateral nucleus
involved in movement especially planning and initiating
dorsal tier of lateral region of thalamus
pulvinar, lateral posterior and lateral dorsal nuclei
input and projection of dorsal tier of lateral region of thalamus
inputs: superior colliculs and association cortex
projects to secondary visual areas and to parieto-temporo-occipital association area
fxn of dorsal tier of lateral region of thalamus
attention and eye movement; probably plays some role in directing attention
metathalamus
medial (auditory) and lateral (visual) geniculate
anterior nucleus of thalamus
afferents from hippocampus and mammillary bodies
projects to posterior cingulate cortex
may fxn in learning and emotions
intralaminar nuclei
centromedian and parafascicular nuclei
afferents from superior colliculus, piriform cortex, and ventral pallidum
project to frontal eye fields and anterior cingulate cortex
fxn in eye-head control and attn
centromedian nucleus
input from globus pallidus
projects to area 4 and entire neocortex
? motor fxn
what separates thalamus and reticular nucleus?
external medullary lamina
reticular nucleus
afferents from brainstem reticular formation, thalmocortical fibers, cortex
Fxns as part of thalamic feedback circuit
? important in sleep/wake
medial MD and midline nuclei
afferents from solitary nucleus, substantia nigra, amygdala, and ventral pallidum
projects to insula, orbitofrontal and subcallosal cortex
fxn in autonomic regulation and emotion
motor unit
single alpha motor neuron and all the muscle fibers it attaches to
motor pool
group of neurons going to muscle
Type I muscle fibers
(red/slow)
small fiber size
small neuron size
moderate speed of contraction
low tension
high aerobic metabolism
fatigue resistant
Type II muscle fibers
(white/fast)
large fiber size
large neuron size
very fast speed of contraction
high tension
low aerobic metabolism
fatigues easily
what do most descending tracts synapse on?
interneurons
lateral motor neurons go to?
limbs
medial motor neurons go to?
axial muscles
tracts that run in lateral funiculus have stronger influence on?
limbs
tracts that run in ventral horn control?
axial muscles
rubrospinal tract
arises from red nucleus
crosses at ventral tegmental decussation
descends in lateral funiculus
controls movements of more proximal limb flexor muscles
tracts that descend in MLF
tectospinal
medial vestibulospinal
pontine reticulospinal
characteristics of tracts that descend in MLF
do not extend beyond upper thoracic region
distribute bilaterally
mainly control axial muscles
tectospinal tract
from superior colliculus with input from cortex, visual, auditory, and somatic sensory systems
descends in MLF and anterior funiculus
terminates in medial part of intermediate gray
crosses at dorsal tegmental decussaion
generates reflex head and eye movement to orient to sudden stimuli
pontine reticulospinal
originates in pontine reticular formation
medial vestibulospinal tract
from medial vestibular nucleus
terminates bilaterally in medial part of ventral horn
reflex adjustment of head position to vestibular stimuli
lateral vestibulospinal tract
from lateral vestibular nucleus
runs lenght of spinal cord in ventral part of lateral funiculus
terminates ipsilaterally at all levels
powerfully excites extensor motor neurons
reticulospinal tracts
control generalized, gross movements, regulates gamma motor neuron activity and sensory transmission
strongly associated with muscle tone--stabilizes trunk as you move
activated by corticobulbar tract
predominantly inhibitory to reflexes
corticospinal tract
voluntary command for movement; can regulate sensory transmission through dorsal horn
arises from motor cortex from Betz cells
axons traverse posterior limb of internal capsule
run through basal pons and comprise pyramids
converge at internal capsule
corticobulbar tract
cortex to brainstem
affect cranial nerve nuclei, sensory transmission nuclei
activate brainstem nuclei involved in movement
project to pons for relay to cerebellum
reticular formation
affect muscle tone, autonomic responses, and level of alertness
fxn of cerebellum
modulates movement--detects motor error and provides corrections to improve performance
regulates activity of upper motor neurons in descending motor pathways
cerebellar input pathways
contralateral from cerebral cortex (via pontine nuclei)
ipsilateral from vestibular nuclei, inferior olive, and cord
output from cerebellum
motor cortex via deep cerebellar nuclei and thalamus
superior colliculus
brainstem motor centers like reticular formation and vestibular nuclei
superior cerebellar peduncle connects?
cerebellum and midbrain
middle cerebellar peduncle connects?
cerebellum and pons
inferior cerebellar peduncle connects?
cerebellum and medulla
vestibulocerebellum
flocculus and nodulus
posture, balance, reflex eye movements
spinocerebellum
vermis and intermediate zone
regulates muscle tone and adjusts ongoing movements
cerebrocerebellum
planning and initiation of skilled movements
paired deep cerebellar nuclei from medial to lateral
fastigial
interposed (globose and emboliform)
dentate
mossy fibers have cell bodies where?
pontine nuclei
vestibular nuclei
spinal cord
climbing fibers have cell bodies where?
inferior olive of medulla
what do mossy and climbing fibers do?
EXCITE Purkinje cells
what do parallel fibers do?
make excitatory connections wiht multiple Purkinje cell that lie in same transverse plane--excitation occurs in rows
what else do parallel fibers excite and what do they do?
inhibit Purkinje cells
stellate cells
basket cells (lateral inhibition)
golgi cells (reduce granule cell activity)
what are the source of output from cerebellar cortex?
Purkinje cell axons
Purkinje cells are what?
INHIBITORY
what does vermis receive info from?
trunk muscles
what does intermediate zone receive info from?
limb muscles
what do cerebellar lesions cause?
persistent errors in movement