Cerebral Hemispheres Flashcards
Define:
Sulcus
Gyrus
Fissures
Sulcus - Depressions on the brain
Gyrus - Elevations on either side of the sulcus
Fissures - Deep Sulci
What is the location of the grey and white matter
Grey matter outside
White matter inside
What is the basal ganglia
Collection on neural cell bodies buried in the white matter
What is the name of the deep fissure that separates the two cerebral hemispheres
Median longitudinal fissure
What is the bridge connecting one cerebral hemisphere to the other
Corpus callosum
What is the fissure called that separates the cerebral hemisphere and the cerebellum
Transverse fissure
What separates the frontal from the temporal lobe
The lateral sulcus
What separates the frontal and parietal lobe
The Central sulcus
What Gyrus sit beside the central sulcus
Infront - Pre central gyrus
Behind - Post central gyrus
What separates the occipital and parietal lobe
Parieto-occipital sulcus
Only seen on the medial surface
What sulci and gyrus sits above the corpus callous
Cingulate sulcus and glyrus
Where is the hippocampus located
Curved under the on the medial surface of the temporal lobe
Where is the insula located
Folded deep within the lateral sulcus
separates the frontal and parietal lobes from the temporal lobe
Name the 4 lobes of the brain
Frontal - Motor Function, Higher Mental Functions and Intellect
Parietal - Somatosensory (touch, temp, pain, pressure)
Temporal - Hearing and Smell
Occipital - Vision
What is the area No.4 in the frontal lobe,
Precentral gyrus
What is the function of area no. 4
Is the primary motor complex (all neurones from here relate to moving muscles in the body)
There is somatotopic representation in the pre central gyrus, what is this
= Motor Homunculus,
which means the amount of space the a muscle group takes up is dependant on how much dexterity a muscle group uses not on the size of the muscle
What is the area No.6 in the frontal lobe,
Pre Frontal cortex
What is the function of area no.6
Organises how muscle groups act together
cognitive functions of higher order- intellect, judgement, prediction, planning
What is area no. 8 associated with
frontal eye fields
What is area no. 44-45
Brocas area of motor speech
How does Brocas area of motor speech work
Thought process feeds into brocas area,
Broca area decides how we formulate what we want to say
Info then goes to percentral gyrus, and stimulates all the muscles we use to talk
What is area, 1, 2 and 3 in the parietal lobe, and where are they exactly located
Primary sensory area lying in the post central gyrus,
What is the function of area 1, 2 and 3 in the parietal lobe
Receives general sensation from contralateral half of the body and has somatotopic representation
What is the functions of the superior parietal lobe
Consciousness awareness of contralateral half of the body
Sensory association area - interpretation of general sensory information
What is the function of inferior parietal lobe
Global association area - makes sense of all information given
How does the location of the inferior parietal lobe aid its function
interface between somatosensory cortex and visual and auditory assocation area
What is the symptoms if lesion occurs in the parietal lobe on the non dominant side
Hemisensory neglect - perceive the sensation but don’t understand they have other half of the body (agnosia)
What is the symptoms in lesion occurs in the parietal lobe on the dominant side
Acalculia - cant count
Agraphia - cant write
What is present in the inferior surface of the temporal lobe, and whats its function
Olfactory bulb, so receives information from olfactory tract for smelling
What is present in the superior surface of the temporal lobe, and whats its function
Auditory association area - makes sense of nose (hearing)
Auditory cortex
What is the location of Wernickes area (41-42)
located in the posterior section of the superior temporal usually the left cerebral hemisphere (commonly the dominant side)
This area encircles the auditory cortex on the lateral sulcus
What is the location of the auditory association area on the dominant side and how does this help its specialised function
Located posterior to Wernickes area and Is further specialised to pick up and decide language on the dominant side of the brain
Where and what is area no. 17 in the occipital lobe
Primary visual cortex located either side of the calcarine fissure
What is the location and function of the calcarine fissure
is located on the medial surface of the occipital lobe and divides the visual cortex into two
What is area no.18-19 in the occipital lobe
Visual association cortex - interpretation of visual images
Where is the limbic lobe found
Found on the medial surface of the cerebral hemisphere
What is included in the limbic system
Cingluate gyrus
The hippocampus
parahippocampus gyrus
amygdala (subcortical grey matter close to temporal pole)
What is the purpose of the limbic system
Memory
Emotional aspects o behaviour
What is the two language areas of the brain
Brocas area (44-45)- production of speech found on frontal lobe
Wernickes area (41-42)-comprehension of speech found unilateral on temporal lobe
What occurs in Wernicks aphasia
Sensory defect in temporal lobe:
Fluent speech with new meaningless words
Cant understand speech
Don’t know mistakes
no paralysis
What occurs in Brocas aphasia
Motor defect in frontal lobe:
Understands speech
Misses small words - can make full sentences
Aware of difficulties in speech
Potential paralysis/weakness on one side of the body
What is white matter composed of
Myelinated axon fibres bundles into tracts
What is the three types of myelinated axon fibres
Commisural Fibres
Association Fibres
Projection Fibres
What is purpose of commisural fibres
Connects corresponding areas of two hemispheres in the corpus callous
What is the purpose of the association fibres
Connects one part of the cortex with another
either long connecting one lobe to another or short connecting a primary area to an association area
What is the purpose of the projection fibres
run between the cerebral cortex and various subcortical centres
What is the internal capsule
Made up of projection fibres passing to and from cerebral cortex
What surrounds the internal capsule, and what affect does this have
Grey matter nuclei: thalamus and Basal ganglia tightly surround the internal capsule creating a densely concentrated V shapped tract that is the internal capsule
What supplies the internal capsule
Middle cerebral artery
What is the clinical affect of internal capsule and its blood supply
Because of dense concentration of fibres if there is an embolism in the middle cerebral artery branch it will end up with very dense stroke as contains alot of fibres that are going to be affected
What is the basal ganglia
Connection of neuronal cell bodies (grey matter) connections sitting in the base of the cerebral hemisphere
(subcortical nuclei deep within cerebral hemisphere)
What is the basal ganglia composed of
Caudate nucleus
Lentiform nucleus (putamen and globus pallidus)
Substantia nigra
Where is the caudate nucleus located
Starts as a large head medial to the internal capsule, a body and slender curving tail which follows curve of the lateral ventricle
Where is the substantia nigra located
In the midbrain
characterised by black line running across mid brain section
What is different to the substantia nigra compared to other basal ganglia components
Non anatomically part of basal ganglia as not located in the cerebral hemisphere but is functionally part of basal ganglia
What lies in the wall of the lateral ventricle
Caudate nucleus
What lies beside the third ventricle
Thalamus
What lies lateral the the caudate and the thalamus
the internal capsule
What lies lateral to the internal capsule
the lentiform nucleus made up of the globes plaids medially and the putamen laterally
What are input region of the basal ganglia
Caudate nucleus and the putamen
Where does the caudate nucleus and the putamen receive information
Motor cortex (4)
Pre motor cortex (8)
Thalamus
How do the caudate and putamen communicate
Via grey fibres called straight nucleus that cross over part of the internal capsule
What is the output region for the input regions of the basal ganglia to feed there information
The globes plaids and the substation nigra
Where is information primary projected to from the output regions of the basal ganglia
Thalamus
After output region send info to the thalamus, where does the thalamus project information
in-turn sends fibres to the motor cortex
What is the overall function of the basal ganglia
Help regulate initiation and termination of movements (overcomes inertia)
Control movement by connecting to motor cortex
What is basal function often called due to its function and why
Extrapyramidal system as feeds back into pyramidal tracts
What occurs in the pathology of parkinson
The neurons of the substantia niagra are dying so cant feed into pyramidal tracts
therefore becomes difficult to initiate movement - shuffle along - then find it difficult to stop and have a mast like face
What over pathologies can arrises from basal ganglia
chorea
athetosis
