neuro revisions Flashcards
how much of the brain is white matter vs grey matter?
grey - 40%
white - 60%
what does the parietal lobe do?
processing sensory info
understanding speech
what does the occipital lobe do?
processes visual info
what does the front lobe do?
thinking cap
decision making
planning
movement
what does the temporal lobe do?
hearing
memory
language
vestibular/balance
what does the insular cortex do?
located deep in lateral fissure
visceral and autonomic functions
sense of taste
what does the limbic cortex do?
emotions and memories
what are the brodman’s numbers for the primary somatosensory area?
3, 1, 2
what is the somatosensory area responsible for?
PRI: size/shape/texture
in central sulcus
SEC: stereognosis/memory of tactile and spatial environment
in parietal lobe
lesions of the somatosensory cortex
PRI: loss of tactile localization/proprioception
SEC: astereognosis
define astereognosis
inability to identify objects by touch only
brodman’s numbers for primary and secondary motor cortex
PRI: 4
SEC: 6
what is the motor area responsible for?
PRI: voluntary mvmts/fine motor mvmts in hand, foot and face
in precentral gyrus
SEC:
PREMOTOR: trunk/girdle muscles
SUPPLEMENTARY: initiation of mvmt
lesions of the motor cortex
PRI: contralateral paresis/loss of mvmt and dysarthria
SEC: apraxia
5 kinds of apraxia
ideational: can perform isolated tasks, but cannot combine them
ideomotor: cannot produce mvmt on command
buccofacial: difficulty with purposeful facial mvmts
limb kinetic: inaccurate/clumsy mvmts of distal limb
dressing - cannot put together the sequence of dressing
describe borca’s area
located in inf frontal gyrus of left lobe
speech production and articulation
lesion:
difficulty expressing using lang
difficulty producing speech
writing affected
expressive aphasia
describe wernicke’s area
located in left temporoparietal cortex
comprehension of lang
understanding spoken, written, signed lang
lesion:
comprehension impaired
produce meaningless words
alexia
inability to write meaningful words
receptive aphasia
brodman’s areas for primary/secondary visual cortex
PRI: 17
SEC: 18-21
what are the functions of the visual cortex?
PRI: light/dark/shapes
located on calcarine sulcus
SEC: analysis of motion, color, recognition of visual objects
located in occipital lobe
what are the lesions of the visual cortex?
PRI: homonymous hemianopia
SEC: visual agnosia/optic ataxia
define homonymous hemianopia
loss of 1/2 of visual field
brodman’s numbers for auditory cortex
PRI: 41
SEC: 22, 42
functions of auditory cortex
PRI: awareness of intensity of sound (dynamics)
located in lateral fissure on adjacent superior temporal gyrus
SEC: classification of sound
located in posterior 2/3 of superior temporal lobe
lesions to auditory cortex
PRI: loss of localization of sound
SEC: auditory agnosia
what is visual agnosia?
impairment in recognizing visually presented objects despite normal vision
prosopagnosia
simultanagnosia
color agnosia
what is auditory agnosia?
inability to differentiate sounds despite intact hearing
phonagnosia - cannot rec familiar voices
amusia - cannot rec different types of music
verbal auditory agnoisa - inability to comprehend spoken word but can read, write and speak normally
dorsolateral prefrontal area
brod: 8, 9, 46
goal oriented and self awareness behavior
located in frontal lobe
parietotemporal area
brod: 39, 40, 7, 19, 21, 22, 37
sensory integration, problem solving and understanding language
located where pari and temp lobes meet
medial dorsal prefrontal area
brod: 8, 9, 10
emotion, motivation, personality
located in frontal lobe
describe the primary vestibular cortex
brod: 40, 21, 22
balance, posture, spatial orientation, self motion perception
located at junction of posterior insula, parietal operculum, retro insular region
lesion of primary vestibular cortex
change in awareness of head position/mvmt and visual perception
could cause vertigo
what is the function of CN 1 - olfactory?
responsible for small
transmits info about odor from olfactory receptors
what if there is a lesion in CN 1?
can lead to a loss or impairment of sense of smell
known as anosmia
what is the function of CN 2 - optic?
transmits visual info to brain
nerve develops from optic vesicle
what is there is a lesion in CN 2?
vision loss - partial or complete
what is the function of CN 3 - oculomotor?
moves eye up, down, medially
raises eyelid
constricts pupil to change lens size
what id there is a lesion in CN 3?
double vision - diplopia
dilation of pupil
eyelid drooping - ptosis
what is the function of CN 4 - trochlear?
moves eyelid medially and down
what if there is a lesion in CN 4?
double vision specifically in vertical field
what is the function of CN 5 - trigeminal?
facial sensation and muscles of mastication
3 branches
- opthalmic - sensation to forehead, upper eyelid cornea and nose
- maxillary - sensation to cheek, top teeth, roof of mouth, part of nasal cavity
- mandibular - sensation to lower jaw, bottom teeth, tongue, innervates chewing muscles
what if there is a lesion in CN 5?
trigeminal neuralgia - sharp burning in face
facial numbness, difficulty chewing, speaking, swallowing
what is the function of CN 6 - abducens?
innervated lateral rectus muscle - abduct the eye
what if there is a lesion in CN 6?
sixth nerve palsy - double vision in eye misalignment
eye may turn inward when looking straight ahead
what is the function of CN 7 - facial?
controls facial muscles/expression, taste salivary and tear glands
sensory: taste and help hearing by innervating parts of ear canal
parasym: salivary and lacrimal glands
5 motor branches
- frontal - forehead
- zygomatic - cheek and eyelid
- buccal - cheek, nose, smile
- marginal mandibular - frown and inner ear
- cervical - platysma, chin/lower mouth
what happens if there is a lesion in CN7?
facial nerve palsy - weakness/spasms, dry eyes, dry mouth, sound intolerance, drooping eyelids, lopsided facial appearance, slurred speech
bell’s palsy: temp facial paralysis that only affects one side
ramsay hunt syndrome: complication of shingles or chickenpox, can present with paralysis, ear pain, rash
what conditions can cause a lesion to CN 7?
guillian barre
tumors in skull
ear infections
stroke
lyme disease
what is the function of CN 8 - vestibulocohlear?
vest: activated with head mvmt, helps carry signals along nerve pathway so brain can process info to maintain balance
coch: sound waves vibrate cochlea and activate nerve to carry signals to brainstem to process sound
what if there is a lesion in CN 8?
hearing loss, ringing in ears, dizziness/vertigo, nystgmus
what is the function of CN 9 - glossopharyngeal?
sensory: sensation from post tongue and pharynx, taste from post tongue, carotid barorecpetors and chemoreceptors
motor: innervates the stylopharyngeus muscle
what is there is a lesion in CN 9?
impaired loss of taste from post 1/3 of tongue
reduced sensation from pharynx
weak or absent gag reflex and swallowing difficulties
what is the function of CN 10 - vagus?
sensory: sensation from larynx and pharynx
motor: innervates muscles of larynx, pharynx, and soft palate which are essential for swallowing and speech, autonomic functions of the gut
parasym: regulating HR, BP, breathing and digestion
what is there is a lesion in CN 10?
laryngeal and pharyngeal paralysis
dysphagia, dysarthria, hoarseness, uvula deviation to unaffected side, parasym dysfunction
what is the function of CN 11 - spinal accessory?
innervates SCM and traps enabling head and neck mvmt and shoulder elevation
what happens if there is a lesion in CN 11?
weakness or paralysis of neck and shoulder muscles
could cause difficulty turning head, shrugging shoulder, possible shoulder drooping
what is the function of CN 12 - hypoglossal?
innervates muscles of tongue
what if there is a lesion in CN 12?
weakness, atrophy, possible fasciculations of tongue, deviations of tongue to side with lesion
what are the four functional groups of the brainstem?
CN nuclei and related structures
long tracts
cerebellar circuits
reticular formation and related structures: consciousness and autonomic functions
how is the brainstem longitudinally divided?
ant: basilar (descending
post: tegmentum (ascending)
midbrain only: tectum
what are the descending axons in the basilar section?
corticospinal
corticobrainstme
corticopontine
corticoreticular
what are the motor nuclei in the basilar section?
substantia nigra
pontine nuclei
inferior olive
what are the components of the tegmentum section?
sensory nuclei and ascending sensory tracts
CN nuclei
MLF - coordinates eye and head mvmt
reticular formation
what is the function of the tectum?
reflexive control of intrinsic and extrinsic eye muscles and in mvmts of head
pretectal area
superior and inferior colliculi
what are the ascending vertical tracts in midbrain?
DCML
spinalthalamic tract
what are the descending vertical tracts in midbrain?
motor:
cortiospinal
corticobrainstem
corticoreticular
corticopontine
autonomic:
sym
parasym
describe the DCML
fine touch and proprio
fasciculus gracilis - lower limbs and trunk
fasciculus cuneatus - upper limbs, trunk and neck
describe the spinothalamic tract
crude touch, pain, temp
3 order neurons
what is the function of the corticospinal tract?
control voluntary mvmt of limbs and trunk
what is the function of the corticopontine tract?
involved with motor coordination
what is the function of the corticoreticular tract?
regulate posture, muscel tone, reflexes
what is the function of inferior colliculi?
relay auditory info from cochlear nuclei
what is the function of superior colliculi?
receives sensory/motor info involved in reflexive head and eye mvmts
what is the function of the reticular activating system?
activates entire nervous system
what is the function of the pons?
facial expression
sensation of taste
move leyes laterally
hearing and balance
planning signals
what are the functions of the medulla?
control of head mvmts
coordinates swallowing
regulates cardiovascular, respiratory and visceral activity
what are the arteries of the circle of willis?
2 anterior cerebral arteries
2 posterior cerebral arteries
1 anterior communicating artery
2 posterior communicating arteries
2 internal carotid arteries
2 middle cerebral arteries
the anterior cerebral arteries brach from which arteries?
internal carotid arteries
anterior circulation
the posterior cerebral arteries brach from which arteries?
basilar artery which is formed by the vertebral arteries
posterior circulation
what does the posterior cerebral artery supply?
occipital lobe
thalamus
midbrain
inferomedial temporal lobe
what does the middle cerebral artery supply?
most of lateral hemisphere
genu of internal capsule
basal ganglia - globus, body of caudate, putamen
what does the anterior cerebral artery supply?
parietal lobe
medial frontal lobe
putamen
anterior limb of internal capsule
anterior caudate
what happens in an occlusion of the anterior cerebral artery?
personality changes
contralateral hemiplegia and sensory loss
more severe in LOWER limb
what happens in an occlusion of the middle cerebral artery?
homonymous hemianopia combines with contralateral hemiplegia and hemisensory
loss involved with UPPER limb and face
language affected if in left hemisphere
nonverbal communication if in right
what happens in an occlusion of the posterior cerebral artery?
thalamic syndrome:
eye mvmt paresis/paralysis
affects muscles controlling eye mvmt
cortical blindness
visual agnosia
how is CSF formed?
from blood filtration, active transport and facilitated transport
where is CSF mostly secreted?
choroid plexuses in ventricles
what are the functions of CSF?
protects CNS
regulates extracellular fluid
removes metabolites from brain
what is the flow of CSF through ventricels?
choroid plexuses
2 lateral ventricles
interventricular foramen (monro)
3rd ventricle
cerebral aquaduct
4th ventricle
down spinal cord in the central canal
drains into subarachnoid space via luschka (lateral) and magendie (medial)
absorbed nto venous sinuses via arachnoid ville
what are the three layers of meninges?
dura mater - surrounds brain inside skull
arachnoid - attached to dura
pia mater - innermost layer attached to brain and SC
what are the 3 meningeal spaces?
epidural - between skull and dura
subdural - between dura and arach
subarachnoid - between arach and pia - filled w CSF
what is a CSF leak?
CSF escapes from subarachnoid space through hole in dura
results in spontaneous intracranial hypotension
what is hydrocephalus?
build up of pressure causing enlargement of ventricles
due to blockage
communicating: ventricular system intact, blocked after 4th ventricle
non-communicating: blockage within ventricular system - most commonly in cerebral aqueduct
what is a subarachnoid hemorrhage?
leakage of blood into CSF by trauma or aneurysm rupture
