Neuroanatomy Flashcards
what makes up the brainstem
midbrain, pons and medulla oblongata
function of astrocytes
support and maintenance of the BBB and environmental homeostasis
function of oligodendrocytes
produce myelin in CNS
true/false - oligodendrocytes myelinate cells in the PNS
false
function of microglia
immune monitoring and antigen presentation
what are ependymal cells and where are they found
ciliated cuboidal/columnar epithelial cells lining ventricles
what is found in grey matter of the brain
neuron bodies, cell processes, support cells and synapses
what is found in white matter of the brain
cell axons, support cells
what is the internal capsule
white matter connecting deep grey matter to the brainstem and higher centres
what is the significance of the calcarine sulcus
border for the primary visual cortex
border of the frontal lobe
central sulcus
border of the parietal lobe
central sulcus
parieto-occipital sulcus
lateral fissure
border of the occipital lobe
parieto-occipital sulcus
lobes of the brain
frontal parietal occipital temporal insular
function of the insular lobe
perception of pain
true/false - grey/white matter in the spinal cord is reversed
true
the H shape of the grey matter of the spinal cord makes up?
ventral and dorsal horns of the cord
the spaces of white matter of the spinal cord make up?
ventral, dorsal and lateral columns
describe passage of CSF through the ventricular system of the brain
lateral ventricle to third ventricle by the interventricular foramen
third to 4th by cerebral aqueduct
leads to central canal as well as openings for subarachnoid space
two plexuses found in the ENS
myenteric plexus
submucosal plexus
venous drainage from the brain
dural venous sinuses drain blood to IJV through jugular foramen
what two pairs of arteries supply the brain
vertebral and ICA
what forms the posterior cerebral arteries
vertebral arteries coming together with the basilar artery
what forms the anterior and middle cerebral arteries
ICA, which gives off anterior cerebral and leads to middle cerebral
what does anterior cerebral artery supply
medially from frontal lobe to parieto-occipital sulcus
what does middle cerebral artery supply
extensively over lateral surface of the brain
what does posterior cerebral artery supply
occipital lobe, inferior temporal lobe
what is the circle of willis and what makes it up
anastomosis of arteries in the brain
anterior cerebral arteries
middle cerebral artery
posterior cerebral arteries
where does the spinal cord end and what is its ending called
L1/2
conus medullaris
what is the filum terminale
thin connective tissue connecting conus medullaris to the dorsum of the coccyx
what is the denticulate ligament
meningeal tissue tethering the spinal cord at each spinal level
the dura mater doesnt attach to the vertebrae to act like the periosteum like it does in the skull. what is its replacement
the epidural fat pad
besides the anterior and posterior horns, what other horn is present T1-L2
lateral horn for SNS transmission
longitudinal arteries to the spinal cord?
anterior spinal artery
posterior spinal arteries
segmental arteries to the spinal cord?
vertebral, intercostal, lumbar
what are the radicular arteries
arteries travelling along dorsal and ventral roots
what venous plexuses drain blood from the spinal cord and where are they found
anterior internal vertebral venous plexus
posterior internal vertebral venous plexus
epidural fat pad
where is the primary somatosensory cortex located
postcentral gyrus
beginning from the longitudinal fissure and working laterally, outline sensory perception in the postcentral gyrus
genitals toes and feet legs hip trunk neck arm hand fingers eye nose face pharynx abdomen
true/false - space in the primary somatosensory cortex is allocated based on the size of organs/body parts
false - it is based on their nerve endings and sensitivity
where is the primary motor cortex located
precentral gyrus
beginning from the longitudinal fissure and working laterally, outline motor perception in the precentral gyrus
toes and feet legs and hips trunk neck upper limb hand eyes nose mouth jaw tongue and swallow
ascending spinal tracts - responsibility of the dorsal column
fine touch, proprioception
where do nerve fibres cross to the other side of the brain in the dorsal column
medulla oblongata
ascending spinal tracts - responsibility of the spinothalamic tract
pain, temperature, deep pressure
descending spinal tracts - responsibility of the corticospinal tract
fine, precise movement
describe lower body sensory information reaching the brain via the dorsal columns
enters spinal cord dorsally and medially into dorsal fasciculus gracilis and ascends by 1st order neuron to medulla
synapses on nucleus gracilis
2nd order crosses midline immediately to the medial lemniscus and to thalamus
synapse with 3rd order to primary somatosensory cortex
describe upper body sensory information reaching the brain via the dorsal columns
enters spinal cord dorsally and laterally into dorsal fasciculus cuneaus and ascends by 1st order neuron to medulla
synapses on nucleus cuneaus
2nd order crosses midline immediately to the medial lemniscus and to thalamus
synapse with 3rd order to primary somatosensory cortex
describe passage of sensory information reaching the brain by the spinothalamic tract
enter dorsal column and synapse to 2nd order neuron, cross the cord and enter the spinothalamic tract anterolaterally
pass through brainstem straight to the thalamus, synapses to third order neuron and onto primary somatosensory cortex
describe passage of motor info from brain to exit of spinal cord by CST
fibres from primary motor cortex pass through internal capsule, though midbrain and pons and onto medullas pyramidal tract
most decussate to other side to form lateral CST
some stay to form ventral CST
lateral CST pass to required level and exit
ventral CST pass to required level, cross segmentally and exit
what could a CVA of the internal capsule lead to
lack of control over CST leading to spastic paralysis and hyperflexion of the upper limbs
where does the reticular tract originate and what is its main function
central core of brainstem
functions in actions essential to life
describe the path of the vestibulospinal tract
originates from vestibular nuclei of pons/medulla and descends
true/false - all descending tracts cross the spinal cord
false - the vestibulospinal doesnt
what is brown sequard syndrome and what would the finidngs be in sensory pathways
lateral hemisection of the spinal cord
ipsilateral loss of vibration, fine touch and proprioception
contralateral loss of pain and temperature sensation
location of the cerebellum to the cerebral hemispheres
posteroinferior
lobes of the cerebellum
anteiror
posterior
flocculonodular
what seperates the anterior cerebellar lobe from the posterior
primary fissure
what separates the posterior lobe
horizontal fissure
what lobe of the cerebellum extends across the midline
flocculonodular
what separates the cerebellum from the cerebrum
tentorium cerebelli
what attaches the cerebellum to the brainsrem
superior, middle and inferior cerebellar peduncles
what is the central region of the cerebellum called
vermis
3 layers of the cerebellar cortex
molecular layer
purkinje cell layer
granular cell layer
where do afferent projections to the cerebellum arise from
vestibular apparatus
spinal cord
cerebral cortex
what cells are the cerebellar output and what does it contribute to
purkinje cells
CST, rubrospinal, vestibulospinal
an ipsilateral lesion of the cerebellum leads to ipsilateral/contralateral symptoms and signs
ipsilateral
midline lesions of the cerebellum may lead to?
posture control
vestibular disturbance is caused by lesions in what area of the cerebellum
flocculonodular node
functions of the basal gangli
purposeful movement
inhibits unwanted movement
mosture and muscle tone
structures making up the basal ganglia
caudate nucleus putamen globus pallidus subthalamic nucleus substantia nigra
outcome of the direct pathway of the basal ganglia on motor output
drives area of the motor cortex to stimulate movement
outcome of the indirect pathway of the basal ganglia on motor output
inhibits stimulation of the motor cortex
how does the substantia nigra influence the basal ganglia and what does it do
use of dopamine to enhance the direct pathway and inhibit the indirect pathway
a unilateral lesion of the basal ganglia would have ipsilateral/contralateral effect
contralateral
describe how stimulation from sound in the cochlea leads to nervous innervation
describe to which nucleus this first goes to
movement of hair cells stimulates bipolar neurons that are found on the spiral ganglion
spiral ganglion becomes cochlear nerve and travels to dorsal and ventral cochlear nucleus
what is the origin of CN VIII
cochlear nucleus on pontomedullary junction
describe from the level of the dorsal and ventral cochlear nucleus, the pathway to which sound reeaches the brain
from dorsal and ventral cochlear nuclei some form the trapezoid body by decussating and some stay ipsilateral
synapse in superior olivary nucleus and nucleus of lateral lemniscus
SON fibres travel by lateral lemniscus to inferior colliculus and then on to medial geniculate nucleus of thalamus
passes into sublentiform IC to enter primary auditory area in superior temporal gyrus
describe the frequency that which fibres enter the primary auditory cortex
low frequency enter anterolateral
high frequency enter poasteromedial
why do brainstem lesions never lead to unilateral hearing loss
superior to the cochlear nuclei fibres decussate and so a lesion above the level of the cochlear nucleus would lead to hearing damage in both ears
what is brocas aphasia
damage to left side brocas area leads to difficulty in producing language
no difficulty in comprehension but leads to expressive aphasia
what is wernickes aphasia
patients have difficulty comprehending language
can hear but cannot comprehend and process understandable speech
receptive aphasia
describe the passage of information from the semi circular canals to the first nucleus the vestibular nerve reaches
vestibular nerve fibres make contact with hair cells of semicircular canals which are transmitted to the vestibular ganglion
passed by vestibular nerve to the superior/inferior/medial/lateral vestibular nuclei
describe where information goes from the vestibular nuclei
lateral goes to spinal cord as part of vestibulospinal tract to control muscle tension
also contribute to medial longitudinal fasciculus with CN III, IV, VI
some pass to the cerebellum
some pass through thalamus to reach cortex for conscious sensation
describe how visual information form the eye and retina reaches the brain
projection of light on the retina is inverted on a horizontal and longitudinal axis
nasal retina info crosses optic chiasm and temporal stays same side to enter the optic tracts
synapse in the lateral geniculate nucleus of the thalamus
some enter the pretectal area to control pupillary light reflex
enter optic radiation terminating on primary visual cortex
describe the termination of optic radiations on the primary visual cortex regions and how this leads to differing light perception
lower visual field is projected to gyrus superior to calcarine sulcus
upper visual field is projected to lower calcarine sulcus
describe the pupillary light reflex
direct light reflex - light causes eye to constrict
information from optic nerve synapses in pretectal area and relates to EW nucleus, leading to parasympathetic down oculomotor constricting the pupil
these happen bilaterally, leading to the indirect light reflex from the othe EW nucleus
lesions of the optic nerve cause
monocular blindness
lesions of the optic chiasm lead to
bitemporal hemianopia
lesions of optic radiation lead to
homonymous hemianopia
what is an association fibre
connect cortical sites of the same hemisphere
what is a commisural fibre
carry info from one hemisphere to the other ie corpus callosum
what is a projection fibre
connect hemisphere to deeper structure
eg internal capsule
