Cerebral Cortex and Blood Supply Flashcards

1
Q

Frontal Lobe

A
  • extends from front of brain to central sulcus
  • separated from temporal lobe by sylvan fissure
  • functions:
  • reasoning
  • planning
  • parts of speech
  • broca’s area: speech production-tells brain how to form words for speech; expressive aphasia: inability to produce language
  • movement: primary motor cortex
  • emotional control center: emotionally labile–>less inhibition/control over emotions
  • problem solving
  • personality
  • impulse control
  • social and sexual: aggressive toward you
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2
Q

Corpus Callosum

A
  • large C-shaped band of white matter that connects the two hemispheres
  • located on the medial surface of the cortex
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3
Q

Function of White Matter/Types of White Matter Fibers

A
  • association fibers: link one area of brain to another (usually same side i.e. Broca’s to primary motor cortex)
  • commissural: link one side of brain different fibers send different messages to other side (i.e. corpus callosum)
  • projection: send communication to other parts of body
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4
Q

Parietal Lobe

A
  • does not have a sharp separation from other lobes on lateral surface, but on medial surface the parieto-occipital sulcus separates it from the occipital lobe
  • functions:
  • movement
  • orientation
  • recognition
  • perception of stimuli, knowing what things mean
  • knowledge of numbers and their relation
  • manipulation of objects
  • sensation
  • R parietal injury/disorder, problems w/ L side body (usually hemineglect)
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5
Q

Insular Lobe

A
  • buried in sylvian fissure

- covered by frontal and parietal operculum

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6
Q

Temporal Lobe

A
  • contains hippocampus
  • formation of LTM
  • contains amygdala: memory, emotion, fear
  • functions:
  • perception
  • recognition of auditory stimuli
  • memory
  • speech
  • left hemisphere: Wernicke’s area-understanding of written and spoken language; receptive aphasia-impaired language comprehension, fluent but meaningless speech
  • this is where we attach emotional stimulus to a memory
  • arcuate fibers go from Wernicke’s to Broca’s (association fibers)
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7
Q

Primary Motor Cortex

A
  • in precentral gyrus in frontal lobe
  • controls contralateral movement
  • dysarthria: patient can’t articulate d/t motor weakness in mouth (i.e. drooling, can’t close mouth completely one side of mouth gaping)
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8
Q

Primary Somatosensory Cortex

A
  • located in the postcentral gyrus of the parietal lobe

- controls contralateral sensation

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9
Q

Topography

A
  • sensory and motor pathways are mapped to adjacent fibers and regions
  • somatotopic maps are called motor or sensory homunculus “little man”
  • areas of cortex correspond to different body parts for both motor and sensory components
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10
Q

Primary Visual and Auditory Cortex

A
  • primary visual cortex: occipital lobe surrounding the calcarine fissure
  • primary visual cortex: temporal lobe, transverse gyri of Heschl, superior surface, in lateral sulcus
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11
Q

Broca’s and Wernicke’s

A
  • broca’s: inferior frontal gyrus

- wernicke’s: superior temporal gyrus

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12
Q

Neocortex

A
  • 6 cell layers
  • Layer I: dendrites from neurons of deeper layers and axons
  • Layer II & III: neurons that project to other layers of the cortex
  • Layer IV: receives majority of input from the thalamus
  • Layer V: projects to brainstem, SC, and BG
  • Layer VI: projects primarily to the thalamus
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13
Q

Classification System

A
  • classification system for different regions of the cerebral cortex based on the appearance under a microscope and the function
  • Brodmann’s Classification
  • 52 areas
  • compatible with functional areas
  • so basically sections of brain physiologically and they work together on a common function
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14
Q

Circle of Willis

A
  • practice drawing all parts and labeling what they supply
  • collateral circulation: hope that if you lose one area another will be able to pick up slack and supply brain
  • 15% have perfect circle but just because it’s symmetrical does not mean that it’s perfect
  • 34% have complete ring
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15
Q

Hemiplegia

A

-paralyzed on one side of body

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16
Q

Hemiparesis

A

-weakness on one side of body

17
Q

ACA

A
  • supplies cortex on anterior medial surface from frontal to parietal
  • somatosensory and motor deficits of the contralateral LE
  • interhemispheric fissure
  • branches: pericallosal a., callosomarginal a.
18
Q

MCA

A
  • aphasia, hemineglect, hemianopia, face-arm or face-arm-leg sensorimotor loss
  • lateral fissure: superior division a., inferior division a., deep territory division
  • supplies most of the lateral and anterior circulation of the cortex: cortex above and below lateral fissure-lateral temporal lobe and frontal lobe, portion of parietal lobe
19
Q

PCA

A
  • supplies inferior and medial temporal lobes and medial occipital cortex
  • contralateral homonymous hemianopia
20
Q

Watershed Infarcts

A
  • regions between cerebral arteries
  • more susceptible to ischemia and infarction when both are compromised
  • can produce proximal arm and leg weakness
  • aphasia syndromes
21
Q

TIAs

A
  • transient ischemic attack
  • neurologic deficit lasting less than 24 hours
  • typical is 10 minutes
  • warning sign to CVA
  • mini-stroke
22
Q

Ischemic CVA

A
  • blood supply is interrupted to a region of brain
  • brain tissue death (infarction)
  • thrombosis: local blood clot forms and occludes vessel
  • embolism: blood clot breaks off and travels to brain and occludes a vessel
  • small vessel infarct: “lacunar infarct” thrombosis
  • large vessel infarct: embolism
23
Q

Carotid Stenosis

A
  • atherosclerosis leads to stenosis of internal carotid artery
  • a thrombosis in this area leads to a TIA or infarct in the carotid branches-MCA, ACA
  • contralateral face: arm or face-arm-leg weakness (MCA)
  • visual field deficits (MCA)
  • aphasia (MCA)
  • neglect (MCA)
  • contralateral leg weakness (ACA)
24
Q

Venous Drainage

A
  • drainage of the cerebral hemisphere occurs through superficial and deep cerebral veins
  • superficial veins drain into the superior sagittal sinus and cavernous sinus
  • deep veins drain into great vein of Galen
  • ultimately enters the internal jugular vein via the transverse and sigmoid sinuses