Exam 2 Week 4 Content Flashcards
where is the diencephalon
in the cerebrum
what are the 4 parts of the diencephalon
the subthalamus, epi, hypo and thalamus
where is the thalamus located
in the center of the brain
what is the thalamus important for
important processing center
TF: nearly all pathways projecting to the cerebral cortex synapse first in the thalamus
true
does olfactory information synapse in the thalamus
no!
the two lateral portions of the thalamus are connected by the
intermediate mass
describe the sensory inputs and nuclei of the thalamus
each sensory input has a spot in the thalamus, a nuclei it synapses wth before going to the cortex.
the medial geniculate nuclei is for
auditory
the lateral geniculate nuclei is fro
visual
thalamic nuclei process info coming from…. (ITS A RELAY)
the BG, cerebellum, limbic paths and brainstem reticular formation
which are there more of corticothalamic projections or thamaocortical projections? why??
corticothalamic, beccasse there is dense reciprocal feedback connections from the cortical areas.
the thalamic nuclei are divided into 3 main groups…
relay nuclei
association nuclei
nonspecific nuclei
the 3 main thalamic nuclei groups are divided by the
internal medullary lamina. (y-shaped white matter)
which nuclei makes up most of the thalamus
relay
what is the purpose of the relay nuclei
they get info from a bunch of different places, and projects it to the cortex. also gets a lot of reciprocal feedback
somatosensation from the spinal cord relay in the, whereas with cranial nerves…
then they go to the
VPL
VPM
both go to sensory cortex
visual information is relayed in the and
LGN
auditory information is relayed in the
MGN
what are the motor relay nuclei
the ventral anterior and ventral posterior
what are the sensory relay nuclei
VLP, VPM, MGN, LGN
where does the VL (ventral lateral) project to
the motor, premotor and supplementary motor cortex
where does the VA (ventral anterior) project to
the motor planning areas.
there are three categories of association nuclei, what are they
decorative memory (AN, LD, M) sensory integration (LP, L) emotion (MG)
what are the non specific nuclei
I (intralaminar)
R (reticular)
where is the hypothalamus in relation to the thalamus
anterior and inferior
what does the hypothalamus integrate
behaviors and visceral functions.
what are the 6 functions of the hypothalamus
homeostasis eating, reproduction, defensive emotional circadian rhythm endocrine regulation activation of SNS
where is the epithalamus in relation to the thalamus
posture and superior
the epithalamus has two parts, what are they
the habenula, and the pineal gland.
what does the habenula do
respond to odor (emotional and visceral response)
what does the pineal gland do
sleep wake cycle modulation, biological clock, onset of puberty, influences secretion of other things.
where is the subthalamus in relation to the thalamus
inferior
what is the subthalamus involved in
controlling motor function
the subthalamus is part of what circuit. why/how do we know?
the BG. contains sub-thalamic nuclei of the re nuclei and the substantial nigra.
what is the role of the subthalamus
controlling motor function
what do the subcortical white matter gibers do
convey signals to and from the cortex.
what are the three types of subcortical white matter fibers
projection, commissural and association
where do the ascending and descending projection fibers go
ascending, subcortical to the cortex.
descending, cortex to things like the SC and brainstem, BG or thalamus.
almost all projection fibers go through the
internal capsule
the anterior limb of the internal capsule has fibers going from the
corticopontine and thalamus to the limbic system
the genu of the internal capsule has fiber from the
CN motor nuclei to the reticular formation
the posterior limb of the internal capsule has fibers from the
corticospinal and thamaocortical fibers to the cortex (somatosensation, visual and auditory, and motor)
what are commissural fibers
between the hemispheres(connects lobes), through the corpus callosum
what are the association fibers. short vs. long?
connect within one hemisphere.
Short: between gyri
long: within the lobes of the hemisphere.
what is the cerebral cortex
a group of cell bodies, axons and dendrites in the grey matter on the surface of the hemispheres.
what two cells make up the cortex
granule and pyramidal
what are granule cells
they are the small interneurons within the cortex
what are the pyramidal cells
these are the outputs for the cortex, so the protection, association and commissural
what is brodmanns area
what they used to map the brain, and which part of the cortex was responsible for what
the primary sensory and motor cortex represents movement and sensation on the ___ side of the body
contralateral
what are somatotopic maps
areas of the brain that are topographically mapped, so the hand is near the arm kind of mapping.
what are the 5 functions of the cortex
primary sensory primary motor secondary sensory motor planning association
where is the primary somatosensory cortex, and what does it do
on the post central gyrus. this is where we discriminate among different intensities, and qualities. discriminate size, shape and texture.
where do the primary
auditory
vestibular
visual cortexes get their information from
cochlear
vestibulothalamocorticol
LGN
what tracts are to the primary sensory cortex
DCML and thalamocortical
where is the primary motor cortex, and what tracts are here
the pre central gyrus. the corticospinal
the corticospinal tracts cross where
pyramids of medulla
what is the function of the primary motor cortex
to control motor outputs, use the plan. control contralateral voluntary movement.
what is the secondary sensory cortex
where we analyze information, and it can tell us what the object is. The primary tells us the object is long and thin, and secondary tells us its a pen.
stereognosis happens here
the secondary sensory cortex.
where and what is the motor planning area.
anterior to the primary motor cortex, plans postural control, trunk and girdle movements.
what are the three areas of the motor planning area
supplemental ,
premotor
Brocas
what is Broca’s area
motor of speech. movement of the tongue, teeth and mouth, allows us to speak. In the Left hemisphere.
what is the association area
not part of sensory or motor, it just associates what things are?
how is sound transmitted
the external meatus, to the tympanic membrane, through the ossicles, to the oval window. From here, it goes to the cochlea, moves the fluid, and the hair cells pick up on it and pass it to CN8
the vestibular apparatus has two parts, what are they
the bony and membranous labyrinth
what is in the bony labyrinth
the perilymph, and it suspends the membranous labyrinth
what is in the membranous labyrinth
the cochlear duct, the utricle and saccule and the semicircular canals, with the ENDOLYMPH
what is ultimately the thing that sends signals to CN 8
the hair cells
what are the semicircular canals
they are 3 hollow perpendicular things
where do the semicircular canals open into
the utricle
what are the ampulla
the fat part right before they SC canals open into the utricle.
the endolymph of the semicircular canals picks up on what movement
rotational acceleration and deceleration
what is located within the ampulla, and what is it
the crista, which is the supporting cells and the hair cells
what are hair cells in the crista of the ampulla embedded in
cupula, which is like jello
hair cells turn mechanical force in to
impulses
what ho the hair cells have
sensory neurons, multiple small stereo cilia and a large kinocilia.
if you move to the kinocilium are you exciting or inhibiting
exciting
away from the kinocilium is
inhibition
describe how head movement affects the cupula
the head moves one way, and the cupula will move another. They normally fire at a baseline rate, with the head still. Then when the head moves, there is a lag, and the lag causes the hair cells to move as well.
what are the otolithic organs
the utricles and saccules.
what types of movement do the otolithic organs picks up. orientation?
head position with gravity, and linear acceleration and deceleration.
utricles: horizontal
saccules: vertical
each sac of the otolithic organ has a
macula
what is the macula. (contains…?)
the hair cells in the jello, with the Ca carbonate crystal over the hair cells, OTOCONIA
how do the hair cells in the macula tilt
the head moves, the otoconia will tilt, and cause the hair cells to move.
what is the maximal response of the utricles
upright and full tilt forward, linear acceleration and deceleration
what is the maximal response of the saccules
from SL to standing, from a lateral flexed position.
where do vestibular nuclei reside int he brainstem
at the pontomedullary junction
the vestibular system contributes to
head movement, position with gravity, eye movement and control, postural adjustments, ANS things like nausea and vomit.
what is the lateral vestibular nuclei
the lateral vestibular spinal path starts here, travels down SC and goes to the trunk and limb muscles for posture and stabilization and maintaining a center of gravity.
what is the medial vestibular nuclei
the medial vestibular spinal tract starts, travels to the cervical spine, and innervates the neck and head for movement control, and positions
fibers from the medial vestibular nuclei go to the … which connect with what
MLF, connects with the extra- occular muscle nerves, the superior colliculi (turn the head and eyes to a noxious stimulus). CONTROLS THE VOR
what is gaze stabilization
the VOR, or the ability to stabilize an image while your head is moving.
when your head turns to the right, what happens to the R and L horizontal canals
the right increases the signal, an the L decreases, so we know which way we are turning.
VOR moves the head and eyes in ___ directions, to maintain visual stability
opposite
describe the path that rotary acceleration and deceleration lead to eye movement
the semicircular canals pick up on it, travels to vestibular nuclei, then the CN extra occular nuclei, then the eyes move.
when you tilt you head down, what do your eyes do
lift up
what kind of information goes into the vestibular nuclei
the vestibular, visual, proprioception, auditory, and tactile
what are some of the regions the vestibular nuclei sends information to, and what do they control
the vestibular cortex (head and neck position)
eye cranial nerves (control eye movement)
superior colliculi and CN 11 (turn the head to stimuli)
cortex, SC and reticular formation (movement of the head and the body)
reticular formation (movement, and nausea, vomit, and changes in consciousness.)
what can impairments of the perception of the body lead to
vertigo, head or body tilt, or decreased orientation
what can impairments in the oculomotor system lead to
oscillopsia (things appear to move when they are not)
diplopia
nystagmus
what can impairments in postural control lead to
ataxic gait, unsteady, lack of stability, leads to balance problems
why is the vestibular system so important
big part of the postural control
what allows the light to enter the eye, and focus and refract light
the cornea
what is the dense outer white of the eye
sclera
the iris is the
smooth muscle with the sphincter pulpilbrea.
the iris has PNS and SNS control of the pupil. which does what
the PNS is the oculomotor, and it constricts, and the SNS dilates
what is the opening at the center of the iris
the pupil
in front of the lens is ___ humor and behind is
aqueous
vitreous
what do the suspensory ligaments connect
attach the lens to the ciliary body
what are the tunics of the eye
fibrous (sclera and Cornes)
vascular (choroid, ciliary, iris)
nervous (retina)
what does the retina contain
the rids and cones, which pick up light
the fovea does what
directs the light to the photoreceptors.
are there more rods or cones
rods
which has poor resolution and is good at night
rods
which picks up on color
cones.
which has more in the fovea
the cones.
what has the blind spot
the optic disc
where is the best acuity
the fovea centralis
on the retina, the light is ___ and ____
inverted and reversed
if it comes into the upper visual space, it goes to the ___ retina
lower
info from the right visual space goes to the ___ hemispheres of each eye
left
what indicates negative visual changes
scotoma/ visual field defects, lesions, dark brown, purple, white areas, absent vision.
what are some characteristics of ischemia to the retina
amaurosis fugax (transient monocular blindness)
brown out
monocular loss for 10 minutes
ipsilateral carotid artery stenosis can cause
retina ischemia
what gives collateral flow in the area of the macula and occipital pole
the MCA and PCA
what happens with ischemia to the LGN or the primary visual cortex
contralateral homonymous hemianopia
the primary visual cortex is supplied by the
PCA
the dorsal path (visual) answers what question and goes where
the parietal occipital and answers where. motion and spatial awareness.
the ventral paths project to what, and answer what
the occipitoemp association cortex, answers what. regions, color, faces, letters, stimuli
a pituitary gland can affect what structure
the optic chasm
where do optic fibers go
the LGN
if they bypass the LGN, where do they go
the superior colliculi, for directing visual attention towards a stimulus
