Cerebral Hemispheres Flashcards
What connects the R and L cerebral hemispheres
Corpus callosum
What are the 5 cortical lobes
Frontal
Parietal
Occipital
Temporal
Limbic
What is the function of the frontal lobe
Motor function, intellect
What is the function of the parietal lobe
Somatosensory
What does the primary sensory areas and association areas do
Primary sensory: Receives information from the sensors
Association: makes sense of the information the primary area has received
For all sensations you have a primary area and adjacent association area
What is the role of area 4: precentral gyrus
Primary motor cortex
Somatotopic representation of contralateral half of body (motor homunculus)
(Entire opposite half of the body represented somatotopically)
What is the role of areas 6 & 8
Prefrontal cortex
Once the cognition are (prefrontal cortex) decides what to do, area 6 & 8 make sense of this and order area 4 (primary motor cortex) to contract muscles in sequence to create meaningful movement
What is the role of area 44,45: inferior frontal gyrus
Broca’s area of motor speech
Makes the instructions into words and sentences then ensures area circled in prefrontal cortex speaks coherently
What does the motor and sensory homunculus represent
More muscular activity and fine muscular activity involved in the precentral & postcentral gyrus, the greater the proportion of the brain it takes up.
When reflected as a person called a homunculus
What is the role of areas 3,1,2: post-central gyrus
Primary sensory area
Receives GENERAL sensations from contralateral half of body (somatotopically represented)
What is the role of the superior parietal lobule
Wherever there is a primary area there is an association area just behind it
Superior parietal lobule lies behind 3,1,2 - therefore it is the association area responsible for conscious awareness of contralateral half of the body
What is the role of the inferior parietal lobule in dominant hemisphere
Language functions
What is the role of areas 41 & 42: superior temporal gyrus
Primary auditory cortex
Site for hearing
What is the role of Wernicke’s area (posterior to 41,42) in the dominant hemisphere
Understanding of spoken word
What is the role of the temporal lobe
Hearing, smell
What does the inferior surface of the temporal lobe do
Receives fibres from olfactory tract - conscious appreciation of smell
What is the role of the occipital lobe
Vision
What is area 17, either side of the cal caribe sulcus, on the occipital lobe
Primary Visual cortex
What is areas 18,19 on the rest of the occipital lobe
Visual association cortex - interpretation of visual images
What is the role of the limbic lobe (where is it)
Medial surface of the cerebral hemisphere has areas which together form functional limbic lobe
Loop formed that information comes into and gets memorised, involved in controlling emotions
What areas form the functional limbic lobe (4)
Circulate gyrus
Hippocampus
Parahippocampal gyrus
Amygdala
What are the language areas of the brain
Areas 44,45 (Broca’s area for speech)
Wernicke’s area (auditory association area - recognition of speech in dominant hemisphere)
What are consequences of Broca’s aphasia
Understands speech
Misses small words
Aware of difficulties in speech
Damage to frontal lobe —> weakness/paralysis of one side of body
What are consequences of wernicke’s aphasia
Fluent speech with new meaningless words included
Can’t understand speech
Unaware of mistakes made when speaking
Damage to temporal lobe - no paralysis
What are the 3 types of white matter fibres in the brain (what do they do)
CAP:
Commisural fibres (connect corresponding areas of the 2 hemispheres - corpus callosum is largest bundle)
Association fibres (go from one area to another within same hemisphere)
Projection fibres (run to or from the cerebral cortex - e.g. motor information from brainstem to muscles, or sensory information up the brainstem)
What is the difference between short and long association fibres
Short = in the same lobe
Long = in different lobe
Where do ALL projection fibres pass
Internal capsule
What is the internal capsule made up of & what does it do
Made up of projection fibres passing too and from the cerebral cortex
All information passes through this area to reach/come from cerebral hemispheres (bottleneck of information)
what is the blood supply for the internal capsule
Derived from middle cerebral artery (frequently affected in a stroke)
What are basal ganglia
Collections of neural cell bodies (grey matter) buried deep in cerebral hemispheres
What are the 5 basal ganglia
Caudate (one with the tail)
Putamen (are shell)
Globus pallidus
Substantia nigra
Subthalamic nucleii
(Wherever you see lateral ventricles you ALSO see part of caudate nucleus)
What are the globus pallidus + putamen called together
Lentiform nucleus
What do the basal ganglia do
Help regulate initiation and termination of movements
What are some pathologies associated with the basal ganglia
Parkinson’s, chorea, athetosis
How is grey matter and white matter arranged in the brain
Grey matter outer
White matter inner
(Basal ganglia - grey matter found deep in the white matter)
