Glossary of 00-neuroanat-02

Start Studying! Add Cards ↓

symptoms of voluntary motor pathway lesion
decrease in speed and strength of contraction, loss of fine motor control, impaired muscle tone
overall result of voluntary motor pathway lesion
disturbs ability to perform motor tasks
overriding function of voluntary motor path
modulates and directs musc. action, esp. sm. musc. of hand
vestibulospinal pathway – role
coordinate postural movements that maintain balance
sensory input- vestibulospinal path
semicirc. canals, CNVIII-vestibular nucleus of medulla
neurons within mostly lateral (some medial) vestibular nucleus send axons where
caudally in ventral funinculus of spinal cord
purpose of vestibulospinal path neurons
excitatory innervation to extensor ‘antigravity’ musc.
where does the reticulospinal pathway originate
in the reticular formation of the pons/medulla
what type of musc. mainly served by vestibulospinal pathway
where do the pontine reticular formation neurons pass?
caudally in ventral funinculus with vestibulospinal path neurons
function of reticulospinal path neurons
also provide innervation to lower motor neurons to antigravity neurons, but primarily to flexors
what is the reticular formation important for
wakefulness, arousal
what inhibits the vestibulospinal and pontine reticulospinal systems to excite LMN of trunk?
the cerebrum and cerebellum inhibit the vestibulospinal/reticulospinal systems (which innervate the “antigravity muscles”)
what occurs in midbrain lesion where cerebrum cannot inhibit vestibulo/reticulospinal systems
no inhibition = hypertonia, hyperflexia of extensors
decerebrate posture
hyperextension of spine and limbs
what cures decerebrate rigidity
destroying the lateral vestibular nucleus
half-sided paralysis
condition where paralyzed limbs are limp, then later become spastic
“spinal shock”
hypertonia, stiffness
what generally occurs with an upper motor neuron lesion after the spinal shock has resolved?
tendon reflexes greatly exaggerated
do muscles atrophy with upper motor neuron lesion?
no. the lower motor neurons are still passing growth factors to muscles
small twitches
normal plantar response (negative babinsky sign)
normally, toes flex when sole of foot stroked firmly
babinsky sign
if upper motor neuron lesion, toes extend up and fan out = “positive babinsky sign”
other symptoms of decerebrate rigidity
back arched, hyperextended, unconscious (never regained.)
which pathway in the spine is responsible for pain, temperature, and simple touch
spinothalamic pathway
where does the pain, temp, simple touch pathway reside
lateral portion of spinal cord
where is the spinal pathway for descriminating touch
dorsal column pathway
what disease knocks out the pathway for discriminating touch
if dorsal column pathway is damaged what is the gross motor result
difficult to walk, impossible to run
what is discriminating touch
texture size shape, but also footsteps
in what tract do the fibres of the spinothalamic pathway pass
Lissauers tract
arrangment of fibres in spinothalamic path
somatotropic, sacral outermost
how many neurons in a typical spinothalamic path
3 paths of spinothalamic path
1. lissauers tract in 2. cross midline to lateral leminiscus up to thalamus, 3 thalamic neurons to parietal cortex
spinothalamic senses
pain temperature and simple touch
dorsal column path & purpose
discriminating touch and conscious proprioception
# of neurons in dorsal column pathway
usually three
three neurons of dorsal column pathway
1. into root, up in dorsal column to lower medulla: nucleus gracilis and nucleus cuneatus2. 2nd neurons decussate as internal arcuate fibres, pass upwards in medial lemniscus to ventral posterolateral thalamus 3. thalamus  parietal cortex
negative symptom
loss of feeling – deadness
positive symptom
pins and needles (paresthesia) burning feeling
spinothalamic lesion produces
lack of awareness of pain and temperature
result of spinothalamic lesion
cold-blue extremities, hair loss, painless burns
dorsal column lesions produce?
descriminatory sensory loss, loss of two point descriminatory touch, may not be able to distinguish items held in hand
inability to descriminate items found in hand
burning sensation (sometimes sock/glove distribution)
can be due to peripheral nerve problems – assoc. w/diabetes
if can’t sense where limbs are, suspect?
dorsal column problem – disturbed proprioception
ignoring one half of body
perceptual rivalry – sensory inattention
if loss of descriminatory sense, sensory inattention, but not pain and temperature loss, suspect?
contralateral parietal cortex lesion
selective deficit of face/arm leg or trunk, suspect?
selective lesion of cortex
if hemisensory loss of all modalities, suspect
contralateral thalamic lesion
if all problems are on one side, suspect
problem above the brainstem
if losing cranial nerve function on one side, and losing opposite side of body, suspect?
brainstem problem
lesion of pons would cause
complete sensory loss to contralateral limbs, loss of pain and temp on opposite side (alternating lesion)
if pain temp and simple touch lost below a certain level, suspect?
contralateral spinothalamic tract lesion below the given level
if all modalities are lost below a certain level and pain and temp on opposite side, loss of proprioception on same side
partial cord lesion (half of cord)
if bilateral loss of pain and temp, but proprioception spared, suspect
central cord lesion
main functions of frontal lobe
voluntary motor control, personality, intellect, verbal communication
main function of parietal lobe
somatesthetic perception (body, cutaneous/musc., sensations, understanding and utterance of speech
temporal lobe functions
audio and visual memory, interpretation of audio sensations
occipital lobe functions
conscious seeing, integration of movements, focus eye, correlation of visual images with previous visual experience and other sensory stimuli
memory, integration of cerebral activities
what and where is broca’s area
motor speech area, left inferior gyrus of frontal lobe – just anterior to lateral sulcus
what do parahippocampal gyrus and cingulate gyrus do?
relay necortex info- hippocampus and limbic system
function of the basal ganglia
maintain muscle tone and program subconscious sequential postural adjustments
hypothalamus is near what?
3rd ventricle
what does the pineal gland produce
melatonin – related to diurnal or nocturnal cycles
what is the diencephalon comprised of
thalamus, hypothalamus, pineal gland (3rd ventricle is within)
what are the cerebral peduncles?
long descending tracts of white matter from the cortex to the pons and medulla
where is the tegmentum
immediately behind the peduncels
what cranial nerves live within the pons
cranial nerves assoc. with medulla
which is the largest subdivision of the CNS?
three ways the cortex can be divided
functional areas, cortico-thalamic and thalamo-cortical connections and histological differences
what neurons relay information vertically within the cortical columns
stellate interneurons
what neurons inhibit spread of signals laterally within cortical columns
non spiny interneurons
another name for central sulcus
fissure of rolando
how are non spiny neurons insulated
GABA inhibitory neurotransmitter (stops lateral spread of info signals out of column)
what causes epileptic seizures
break down of non-spiny gabargenic neurons
what is another name for giant pyramidal cells
betz cells – control voluntary movement contralateral on anterior wall of central sulcus
where are motor versus sensory cortex areas in relation to central sulcus
motor-precentral gyrus, sensory -post central
what area of frontal cortex is responsible for contralateral conjugate deviation of eyes
frontal eye field of posterior part of middle frontal gyrus
famous yorkshire lunatic asylum neurologist
how does a focal seizure cause symptoms?
spreads through brain, disrupts normal function, activating motorneurons and muscle – causes convulsions
what breaks down during an epileptic seizure
GABA – localized inhibitory surround
how is it possible to tell the site of the epileptic focus in the cortex?
first sign of abnormal motor convulsion or sensation occurs here: i.e. hand or foot
name given to obvious seizure spread slowly across cortex
Jacksonian march
Jacksonian seizures probably occur after many focal seizures why?
Gabargenic response- gradually breaks down insulative barrier – change in excitability – facilitates increasingly easier seizures over time
3rd ventricle within which part of brain
4th ventricle within which part of brain
function of cerebral lobes
voluntary movement, higher intellectual processes and personality
basal nuclei do what
muscle coordination during body movement
which structures monitor respiratory rates
pons and medulla
which part of brain concerned with hearing and seeing
midbrain-superior colliculi, hearing:inf. colliculi
seritonin function
influences body temperature, sensory perception and sleep regulation
end of spinal cord called
conus medularis
where the apneustic and pneumotaxic centres
within the pons
where is the breathing rhythmicity area?
what structure regulates vasoconstriction
what system generates emotions
which system alerts brain
term for progressive ease of seizures
most effective means of producing kindling effect
electrical impulses to limbic system
significance of kindling
treat seizures early
what lobes does the middle cerebral artery pass between
temporal and parietal through lateral fissure
middle artery supplies?
internal capsule, basal nuclei, temporal, frontal and parietal lobes on lateral surfaces
middle cerebral artery damage – what effects?
contralateral hemiplegia, hemianasthesia, aphasia (loss of language), neglect of contralateral limbs
anterior cerebral artery supplies?
medial side of hemispheres, runs above optic nerve, follows corpus collosum, branches to internal capsule and basal nuclei: medial orbital frontal, parietal
one half of body mostly not working, but leg spared – why?
middle cerebral artery occlusion – anterior cerebral serves medial frontal lobe where leg is mapped.
path for speech
cochlea – prim. aud. cortex – wernickes area – arcuate fasciculus – broca’s – motor cortex
path for reading written word
primary visual cortex – angular gyrus – wernickes area
wernickes area – function
associates visual form of word with corresponding auditory pattern
auditory area – where
superior temporal gyrus
damage in what area might damage arcuate fasciculus
supramarginal gyrus
which areas of cortex included in zone of language
brocas, facial motor cortex, angular gyrus, wernickes, auditory cortex
loss of capacity for spoken language
what artery supplies all cortical areas involved in speech
middle cerebral
what does main artery thrombosis of the middle cerebral artery give rise to?
global aphasia
what is language?
formulation, comprehension and use of words and symbols as part of a rule bound socially shared code
what is speech
motor process involving production of sounds for the purpose of transmitting language
creation of new words
what are aphasias usually caused by
lesion in one or more areas of dominant cerebral hemisphere
where is the supramarginal gyrus
above the lateral fissure
what might a lesion to Broca’s area cause
transient aphasia or sometimes apraxia of speech
what is apraxia
faulty programming of speech musculature for sequential movements required by speech
what is the basic cause of apraxia
higher programming level which effects motor production
what are speech difficulties caused by muscular disturbances called
what might effect muscles that control speech
paralysis, weakness, incoordination, varying speed
what might be a sign of mild dysarthria
chronic hoarsness
difference between apraxia and dysarthria
disarthria speech errors are consistent and regular, not predictable. Language itself is not impaired – only speech.
cranial nerves associated with midbrain
cranial nerves associated with pons
cranial nerves associated with medulla
if an alternating lesion, where is it
describe alternating lesion characteristics
weakness on same side for the cranial nerve, weakness on opposite side below the lesion
upper motor neuron path
cortex – internal capsule – brainstem
what % of substantia nigra needs to be involved for motor problems
significance of separate motor and sensory roots for CN V
can cut motor root without effecting sensory
which cranial nerve roots used in speech
5, 7-12
bells palsy symptoms
no forehead lines, can’t close eye, no naso-labial folds, drooping mouth: LMN Lesion

Add Cards

You must Login or Register to add cards