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
-hydrocephalus
-increased vasodialation/obstruction. - Diagnostic tests for CSF
-
-lumbar puncture
-myelography
-imaging
-pneymoencephalography (air)
-ventriculography
-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
-
-headache
-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?
-
-orbial
-frontopolar
-callosomarginal
-pericallosal
arteries - 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?
-
-temporal
-frontal
-parietal
arteries - 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
-hemianesthesia - Other MCA related problems
-
-poor sense of position
-temprorospacial problems
-cont. HH
-apasia, apraxia, dyslexia, dysgraphia --> L MCA
-anosgnosia --> R MCA -
Posterior spinal artery:
--supplies:
--Damage = -
s: medulla, SC
D: DCML, impairs fine discrimination and stereognosis -
Anerior spinal artery:
--supplies:
--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):
supplies
damage= -
s: ipsilateral cerebellum
D: coordination of rapid movements -
Posterior Cerebral artery (PCA)
supplies:
Damage=: -
s: ant. and inf. frontal lobes, inf. and med. occipital lobes, uncus
D: HH, blindness, cerebellar symptoms -
Superior Cerebellar artery
supply:
Damage= -
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?
thrombophlembitis? -
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?
-face/tongue/mouth
-vision
-audition
-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?
-
-stereognosis
-vibration
-propreoception
-kinesthesia
-graphesthesia - 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
-
-scotopic
-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
CIRCULAR muscle
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)