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Neuro Exam 2


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How is CSF circulated?
cillia in ventricles circulate it after choroid plexus creates it
Pathologies of the CSF
-discolored (blood or infection)
-cell count (should be 5 lymphocytes/mL)
-sterile (or else bacterial infection)
-protein concentration (too much = MS, neorosyphillis)
-glucose levels (check for fungus/bacteria)
Patholgies of ventricular system and cortex
-increased brain volume: edema, abcess, neoplasm, hypoxia, infarct, meningitis
-increase focal brain volume: intra-cereb. hemmorhage, neoplasm, tumor
-increased vasodialation/obstruction.
Diagnostic tests for CSF
-lumbar puncture
-pneymoencephalography (air)
-radioisotope brain scan
What does the fasiculus gracillis contain?
epicritic neurons for the lower half of tehe body
what does the fasiculus cuneatus contain?
epicritic neurons from the upper half of the body
What do lesions of the DCML system affect?
disciminative touch, proprioception, kinestieia
tests for DCML lesions
2 pt tactile discrimination, vibratory sense, position sense, stereognosis, graphestisia
what is stereognosis?
ability to identify objects with the hand
what is graphesthesia?
ability to identify letters or numbers traced on the hand or body
what can result from an impairment of the MCA?
contralateral hemiplegia, impaired sensory functions (epicritic and protopathic), haphasia, constuctional apraxia, temperospacial deficits, homonymous hemianopsia, reading/writing deficits
what can result from an impariment of the ACA?
paralysis for legs and feet, prefrontal lobe symptoms, decreased spontinaity, motor inaction, impaired judgement and concentration
what can result from an impairtment of th PCA?
homonymous hemianopsia

if in basilar artery: blindness, pntine and cerebellar issues
Rule for Vascular system disorders:
-sudden development of contr. hemipl. of lower face, arm and upper extremity more than leg with accompanying sensory loss
occlusions of the MCA, caused by thrombosis or embolism
Rule for Vascular system disorders:
-toe, foot, and leg paralysis, sneosry loss, and mental impairments (distractibilty, indecisiveness, lack fo spontaneity)
due to ischemia due to embolism of thrombosis in the ACA disctrubition
Rule for Vascular system disorders:
-HH, low pain threshold
PCA involvement, thalamic involvement
Lesion localization: spinal central gray lesion
bilateral loss of pain and temperature sensation with preserves sense of thouch in the same limbs
Purposes of CSF
-protective mechanism
-chemical resevoir
-boutant environment for brain
-removes brain waste
-reculates extravellular activity
-reduces brain weight
what produces CSF in the ventricles?
chorois plexus
what do the arachnoid velli do?
drain waste from CSF into venous sinuses
what can/not pass from blood to CSF?
yes: h2o, gases, lipid-soluables

nop:macromolecules (protiens and heroses)
Path of CSF in ventricular system
-produced by choroid plexus, moved by cilia
-pumped by cardiac systolic and resp. movements
-lateral ventrical goes to
foramen Monro goes to
3rd ventrical to
cerebral aqueduct to
4th ventricle to
luschka forame and magendie foramen to
subarachnoid space
abnormal sympoms indicating brain problem
-nausea and vomiting
-bradycardia (inc. BP)
-papilledema (inflamed optic disk)
-changes in conciousness
-changes in skull
-stiff neck
componants of the Dura mater
-2 layers of fused connective tissue
-forms falx cerebri
-forms tentorium cerebelli
cranial layers
-cranium, epidural space, dura mater, subdural space, arachnoid, subarachnoid space, pia mater, cortex
purpose of cerebral blood circulation
-nutrition: flucose
-nerve cell metabolism
-provide O2
-remove CO2
What does the external carotid artery supply?
forehead, facial muscles, oral and nasal regions, obital cavities
what does the internal carotid artery supply?
cavernous sinus, anterior choroidal and obthalmic areas
what does the Internal Carotid Artery (ICA) subdivide into?
anterior cerebral artery (ACA)
Middle cerebral artery (MCA)
where does the Anterior Cerebral artery course? (ACA)
projects forward and medially via the interhemisphereic fissure, around the corpus collosum
what does the ACA branch into?

what does ACA anastomos with, and where?
PCA, from basilar arteries

MCA, from ICA (watershed area)
Where does the MCA run, supplying which areas?
runs medially via the Sylvian fissure, supplies lateral surface of cortex
what does MCA divide into?

what special areas does the MCA supply?
-motor speech and motor cortex
-precentral gyrus
-Broccas area
-sensorimotor areas
-somatosensory areas
-Heschl's gyrus (audition)
-angular and supramarginal gyri
-Wernicke's area
MCA lesion symptoms
-general somatosensory problems
-poor tactile distcrimination, astereognosis
-lack of touch, pain, temp. sense
Other MCA related problems
-poor sense of position
-temprorospacial problems
-cont. HH
-apasia, apraxia, dyslexia, dysgraphia --> L MCA
-anosgnosia --> R MCA
Posterior spinal artery:
--Damage =
s: medulla, SC

D: DCML, impairs fine discrimination and stereognosis
Anerior spinal artery:
--damage =
s: lower medulla, ventral 2/3 of SC

D: hemiplegia, epicritic and protopath. hemisense. loss
-lesion above decuss. in medulla: alternating hemiplegia
Posterior inferior cerebellar artery (PICA):

s: ipsilateral cerebellum

D: coordination of rapid movements
Posterior Cerebral artery (PCA)


s: ant. and inf. frontal lobes, inf. and med. occipital lobes, uncus

D: HH, blindness, cerebellar symptoms
Superior Cerebellar artery


s: cerebellum, midbrain

D: motor incoordination, impaired balance, ataxic or flaccid dysarthria
Name some penetrating arteries and what they supply
arteries: medial striate, anteromedial and posteromedial, posterolateral, anterior and posterial choridal

Supply: thalamus, internal capsule, hypothalamus, chorois plexus, basal ganglia, caudate, putamen, GP
what is an embolism?
traveling clot from a detatched thrombosis, trapped in a distal artery
what is a thrombosis?

localized buildup of fat or blood platelets

tbis: traveling clot from peripheral artery
what is a hemorrhage?
ruptured blood vessel
what is an aneurysm?
ballooning of arterial wall
what is an AVM?
congenital condensed capillaries (aterial venous malformation)
define epicritic sensation
discrimination and topogrpahic localiztion of touch, snsation, and temp. stimuli

higher order UMN or CNS cerebral functions
define protopathic sensation
primitive or crude sensation, PNS nerve fibres

lower order pain and temp sensation, pooly localizable
(anterio lateral, spinothalamic tracts)
where are the veins and arteries housed in the cortex?
Veins: in dura mater

arteries: in pia mater
where do these veins collect blood from and dump in to?
-superficial middle cerebral veins
-inferior cerebral veins
-superior cerebral veins
SM: from lateral brian to cavernous sinus

I: from basal surface to cavernous, petrosal, and transverse sinuses

S: from middle surface to superior sagital sinus
what does the anterolateral system do, and where does is project from/to?
-transmits diffuse touch, backup system to somatosensory system

-goes from VPL of thalamus thru internal capusle to post-central gyrus
Damage to Anterolateral system __(here)__ causes what?

-ascending fibers
-spinal nerves (PNS)
-spinothalamic fibers
AF: alters sensation of pain, temp, lght touch, pressure

PNS: burning pain in damage region

SF: prohibits pain/temp transmission to somatosensory cortex
Where are First Order sensory neurons?
-outside CNS in ganglion
-enters SC or BS via dorsal root or sensory cranial nerves
Where are Second Order sensory neurons?
-in dorsal gray matter (SC) or BS
-decussate (BS, if ALS, Medulla if DCML)
-grouped into faccisuli and lemnisci
-reach VPL Nucleus
-terminate in sensory nuclei
Where are Third Order sensory neurons?
-at thalamic level
-axons go thru thalamocortical radiaion to sensory cortex
-reach post central gyrus
where are these senses sensed?
-general somatosensory
-supra-sylvian region

-occipital cortex

-temporal lobe

-parieal and temporal cortex
Lesions of ALS __here__ imply what deficits?

-spinal level
-posterior fossa level
-supratentorial level
SL: segmental deficits, all sensory modalities involved, sensation of pain percieved

PFL: contr. sensory loss (trunk, extremities), ipsilat. sensory loss (face)

STL: entirely contrl. sensory loss
What does the Dorsal Column Medial Lemniscal system perceive?
what is the DCML tract comprised of?
fasiculs gracilis, fasiculus cuneatus
what is the ALS comprised of?
lateral spinothalamic tract, anterior spinothalamic tract
what does the Anterolateral System sense?
pain, temp, diffuse crude touch
What do the __ tracts mediate?

-lateral spinothalamic

anterior spinothalamic
-lat: pain and temp

-ant: crude touch
name some other aceding tracts
-spinocerebellar tract
-spinotectal tract
-spinoreticular tract
-spinal column
4 events contributing to visual perception
1. refraction of light rays via lens and cornea
2. conversion of electromagnetic energy of light to nerve impulse
3. transmission of action potential
4. perception of visual image
discriminate visual field from retinal field
V; area in world you see

R: VF image seen in reverse on retina
Componants and purpose of the Anterior Cavity
contains: iris, cornea, lens, aqueus humor, ciliary body, suspensory ligaments

does: refract light rays and image on retina

contains anterior and posterior chambers
details of Anterior Chamber
-between cornea and iris
-contains aqueous humor
-drains into venous system
-maintains intraocular pressure
details of posterior chamber
-contains lens and suspensory ligament
-contains aqueous humor
-helps maintain intraocular pressure
details of the posterior cavity
-between lens and retina
-contains vitreous humor
-helps maintain intraocular pressure
-keeps eyeball from collasping
name and describe the 3 occular layers
-sclera: dura mater extention and corna

choroid: middle vascular tunic, blood supply

retina: inner nervous tunic
describe the lens
-multiple layers of protien

-behind pupil, suspended

-focus via refraction of light rays onto retina
describethe retina
-posterior 2/3 of eyeball
-10 layers of cells
-rods increase to see black and white
-rods decrease to see color
describe cone cells
phototopic cones, different size for different colors
-function in bright daylight
-sharp visual acuity (color vision)
-high temporal rsolution
describe rod cells
-midate night vision
-funcion in dim light
-differentiate white/gray/black
-detect movement, shapes
what is rhodpscin?
light absorbing molecule
-decomposes and regenerates in 7-30minutes
-nyctalopia (night blindness)
deferentiate the
from the
RADIAL muscles
c: constrictor, decrease pupil size, parasympathetic system

R: increase pupil size, sympathetic system
what is the fovea?
center of the retina, most acute vision, projects to tip of occipital lobe
general neural tract of vision
optic nerve (retina, optic chasm), to optic tract (branch to lateral geniculate body or superior colliculous), thalamus (geniculocalcarine radiations), visual cortex (in occipital lobes)

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