Cerebral Hemispheres (Cerebrum)

Cerebral Hemispheres Cerebral HemispheresFigure 7.13a

gyrussulcusfissures thrown into folds or convolutions known as gyri gyrus seperated from each other by grooves known as sulci or fissures

2longitudinal cerebral fissure separates the cerebral hemispheres contains the falx cerebricorpus callosum connects the cerebral hemispheres across the midline

falxcerebri

3 Lateral surface of cerebrum Medial surface of cerebrumInferior surface of cerebrum Surface of cerebral hemisphere

4 Lateral view hemispheres

frontal parietaltemporaloccipitalfrontalparietaltemporal5

central sulcuslateral sulcusprimary motor area primarysomesthetic areaMain sulci parieto-occipital sulcus(1)(2)(3)1 anterior horizontal2. anterior ascending3. Posterior ramusfrontaltemporalparietaloccipital6

parieto-occipital sulcuscalcarine sulcus7Lobes of the Cerebral HemispheresFrontal lobeParietal lobeTemporal lobeOccipital lobe

FrontalParietalOccipitalTemporal8

Frontal Lobesuperior frontal gyrusmiddle frontal gyrusinferior frontal gyrusprecentral gyrus(A)(P)central sulcuslateral sulcusprecentral sulcussuperiorfrontal sulcusinferior frontalsulcusfrontal lobeorbital portiontriangular portionopercular portion(1)(2)(3)9 Frontal Lobe

MotorCortex contains the primary motor area which carries out individual movements of different parts of the body it also plays a role in a persons feeling and in social judgement 10 Parietal lobe

central sulcuslateral sulcuspostcentral sulcuspostcentral gyrussuperior parietal lobuleinferior parietal lobuleintraparietalsulcus11

somatosensorycortex Parietal Lobe contains areas for sensory reception & integration of sensory information

Temporal lobesuperior temporal gyrusmiddle temporal gyrusInferior temporal gyruslateral sulcussuperior temporal sulcusinferior temporal sulcus14 Temporal Lobe contains primary auditory cortex

TemporalLobeAuditoryCortex Occipital Lobe contains primary visual area also contains 2 structures: cuneus lingual gyrus

OccipitalLobe VisualLobe Functions of Cerebrum LobesFrontal : contains the primary motor area the function of which is to carry out individual movements of different parts of the body; it also plays a role in a persons feeling and in social judgement Parietal : contains areas for sensory reception & integration of sensory informationOccipital : primary visual areaTemporal : primary auditory area17

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insula

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Island lobe20

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228643,1,2171819394041,4245,4422910111234285,723 Medial surface of cerebrum

parietooccipital sulcuscalcarine sulcuscuneus corpus callosumparacentral lobulecingulate gyruscallosal sulcuscingulate sulcusprecuneus medial frontal gyrus24 Medial surface of cerebrum

parietooccipital sulcuscalcarine sulcuscuneuslingual gyruscingulate gyrusprecuneuscollateralsulcusparahippocampal gyrusuncus medial frontal gyrusoccipitotemporal sulcusrhinal sulcusmedial occipitotemporal gyruslateral occipitotemporal gyrus25

Inferior surface of the cerebrumolfactory sulcus olfactorybulbolfactorytractgyrus rectusorbitalgyriuncusparahippocampal gyruslingual gyruscalcarine sulcusoccipitotemporal sulcusmedial occipitotemporal gyrus lateral occipitotemporal gyruscollateralsulcus26

Internal structure of the Cerebral Hemispheres

cerebral cortexcerebralwhite matterbasalnuclei28

lateral ventriclescerebral cortex cerebralwhite matterbasal nuclei29Lateral ventricles

lateralventricles thirdventricleAnterior viewLateral view30

corpusstriatumamygdaloid nucleusclaustrum Basal NucleiBasal nuclei is a collection of masses of gray matter situated within each hemisphere31 The corpus striatum is composed of: caudate nucleus lentiform nucleus globus pallidus putamen internal capsule

caudatenucleusglobuspallidusputameninternalcapsule32 Basal Nuclei

The basal nuclei play an important role in the control of posture and voluntary movement.33 Cerebral White Matterconsists of myelinated nerve fibers classified into 3 groups:

Commissural fibersAssociation fibersProjection fibers

white matter34Commissure fibers connect corresponding regions of the two hemispheres Association fibers connect various cortical regions within the same hemisphereProjection fibers nerve fibers passing to and from the brainstem to the entire cerebral cortex.

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commissure fibersprojection fibersassociation fibers

fornixCommissures 1. corpus callosum: the largest commissure connecting the 2 hemispheres

Commissures 2. anterior commissure : is a small bundle of nerve fibers that crosses the midline in the anterior portion.

Commissures3. Posterior commissure: bundle of nerve fibers that crosses the midline immediately above the opening of the cerebral aqueduct into the third ventricle.

fornixCommissureshabenular commissure4. Fornix : composed of myelinated nerve fibers function of which is to connect the hippocampal formation of the two sides.40

fornixCommissureshabenular commissure5. Habenular commissure:is a small bundle of nerve fibers associated with the habenular nuclei which receive many afferents from the amygdaloid nuclei and the hippocampus. The function of the habenular nuclei and its connections in humans is unknown. 41 Corpus CollasumThis is the large fiber tract that connects the right and left hemispheres of the brain.

corpus callosumcommissure fibers42

rostrumgenubodysplenium Corpus callosum 43

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Association fibersAssociation fibers are nerve fibers that essentially connect various cortical regions within the same hemisphere and may be divided into short and long groups.46

Association fibersAssociation fibers are nerve fibers that essentially connect various cortical regions within the same hemisphere and may be divided into short and long groups.47Association fibers do not leave the cerebral hemisphere, and can be classified as either long or short.

1. The uncinate fasciculus connects the first motor speech area and the gyri on the inferior surface of the frontal lobe with the cortex of the pole of the temporal lobe.

2. The cingulum is a long, curved fasciculus lying within the white matter of the cingulate gyrus. It connects the frontal and parietal lobes with parahippocampal and adjacent temporal cortical regions. 3. The superior longitudinal fasciculus is the largest bundle of nerve fibers connecting the anterior part of the frontal lobe to the occipital and temporal lobes.

4. The inferior longitudinal fasciculus runs anteriorly from the occipital lobe, passing lateral to the optic radiation, and is distributed to the temporal lobe.

5. The fronto-occipital fasciculus connects the frontal lobe to the occipital and temporal lobes.

Projection fibers

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