Cerebral Cortex and Blood Supply Flashcards Preview

DPT 736 Neuroanatomy > Cerebral Cortex and Blood Supply > Flashcards

Flashcards in Cerebral Cortex and Blood Supply Deck (24)
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Frontal Lobe

-extends from front of brain to central sulcus
-separated from temporal lobe by sylvan fissure
-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
-impulse control
-social and sexual: aggressive toward you


Corpus Callosum

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


Function of White Matter/Types of White Matter Fibers

-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


Parietal Lobe

-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
-perception of stimuli, knowing what things mean
-knowledge of numbers and their relation
-manipulation of objects
-R parietal injury/disorder, problems w/ L side body (usually hemineglect)


Insular Lobe

-buried in sylvian fissure
-covered by frontal and parietal operculum


Temporal Lobe

-contains hippocampus
-formation of LTM
-contains amygdala: memory, emotion, fear
-recognition of auditory stimuli
-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)


Primary Motor Cortex

-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)


Primary Somatosensory Cortex

-located in the postcentral gyrus of the parietal lobe
-controls contralateral sensation



-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


Primary Visual and Auditory Cortex

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


Broca's and Wernicke's

-broca's: inferior frontal gyrus
-wernicke's: superior temporal gyrus



-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


Classification System

-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


Circle of Willis

-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



-paralyzed on one side of body



-weakness on one side of body



-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.



-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



-supplies inferior and medial temporal lobes and medial occipital cortex
-contralateral homonymous hemianopia


Watershed Infarcts

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



-transient ischemic attack
-neurologic deficit lasting less than 24 hours
-typical is 10 minutes
-warning sign to CVA


Ischemic CVA

-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


Carotid Stenosis

-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)


Venous Drainage

-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