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
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
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
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)
5
Q
Insular Lobe
A
- buried in sylvian fissure
- covered by frontal and parietal operculum
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)
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)
8
Q
Primary Somatosensory Cortex
A
- located in the postcentral gyrus of the parietal lobe
- controls contralateral sensation
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
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
11
Q
Broca’s and Wernicke’s
A
- broca’s: inferior frontal gyrus
- wernicke’s: superior temporal gyrus
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
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
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
15
Q
Hemiplegia
A
-paralyzed on one side of body
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
