Cerebrum ppt

Cerebrum ppt

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  CEREBRUM BY M.HIMASAILA Assistant professor Sri PadmavathiSchool of Pharmacy CENTRAL NERVOUS SYSTEM
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  Cerebrum  Largest partof the forebrain.  Divided into two halves, the (cerebral hemipheres), which are separated by a deep median longitudinal fissure which lodges the falx cerebri.  In the depth of the fissure, the hemispheres are connected by a bundle of fibers called the corpus callosum. Median longitudinal fissure Corpus callosum Right hemisphere Left hemisphere
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  Superolateral Medial Inferior (tentorial) Surfaces
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   Cerebral cortex:Superficial layer of grey matter  White matter (WM): Deeper to the cortex, contain axons to and from the cells of the cortex  Basal ganglia: Number of nuclear masses buried within the white matter  Lateral ventricle: The cavity of hemisphere Cortex Basal ganglia WM WM Lateral ventricle Structure of Cerebrum
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  Lobes of Cerebrum Thesuperficial layer of grey matter is highly convoluted to form a complex pattern of ridges (gyri) and grooves (sulci). This arrangement maximizes the surface area of the cerebral cortex (about 70% is hidden within the depths of sulci). S g • Three sulci, consistent in position, named central, lateral (sylvian) & parieto-occipital, divide each hemisphere into FOUR lobes: Frontal, Parietal, Temporal & Occipital (named after overlying bones) Functionally each hemisphere contains a ‘limbic lobe’ on the medial surface.
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  motor function, motivation, aggression, smell andmood emotions, memory storage & Linking conscious intellectual functions with the unconscious autonomic functions, smell, hearing, memory and abstract thought visual processing reception and evaluation of sensory information Function of Lobes
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   Frontal lobe: Precentral gyrus.  Superior & inferior frontal sulci divide the lobe into superior, middle & inferior frontal gyri. Superior , middle & inferior frontal gyri Precentral gyrus Superior parietal lobule Inferior parietal lobule Postcentral gyrus Intraparietal sulcus sfs ifs  Parietal lobe:  Postcentral gyrus.  Intraparietal sulcus divide the lobe into superior & inferior parietal lobules.
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   Temporal lobe: Superior & inferior temporal sulci giving rise to superior, middle & inferior temporal gyri.  Insula: the gyrus in the depth of lateral fissure, covered by parts of frontal, parietal & temporal lobes called the opercula (removed in lower picture.). Superior, middle & inferior temporal gyri insula sts its
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  Medial Surface  Sulci:Parietooccipital, Calcarine, Cingulate  Gyri: Cingulate, Parahippocampal
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  • Brodmann produceda numbered, cytological map of cerebral cortex based upon its regional histological characteristics • Subdivisions with similar cellular and laminar structure are called 'areas' • Brodmann's numbering of these cortical locations has become one of the standard ways to identify brain areas. Brodmann’s Map
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  Functional Areas of the CerebralCortex
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  Frontal Lobe Primary motorcortex: Located in precentral gyrus (Brodmann area 4). Premotor cortex: Located in the region immediately anterior to the precentral gyrus (Brodmann’s area 6). Frontal eye field: Located in the middle frontal gyrus immediately in front of motor cortex (Brodmann’s area 8). Broca’s (motor speech) area: Located in the inferior frontal gyrus of the dominant hemisphere, usually left (Brodmann’s area 44 & 45). Prefrontal cortex: Extensive region of the frontal lobe anterior to premotor area.
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  Parietal lobe Primary visualcortex: located on the medial surface of the hemisphere, in the gyri surrounding the calcarine sulcus (Brodmann’s area 17). Occipital lobe Visual association cortex: located around the primary visual cortex. Parietal association cortex: located posterior to primary somatosensory cortex. Primary somatosensory cortex: located in postcentral gyrus (Brodmann’s area 1, 2, 3).
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  Temporal Lobe Auditory associationcortex: located immediately around the primary auditory cortex (also includes Wernick’s area) Parahippocampal gyrus: located in the inferomedial part of temporal lobe. Deep to this gyrus lies the hippocampus and the amygdala, which are parts of limbic system Primary auditory cortex: located in the superior surface of the superior temporal gyrus (Brodmann’s area 41, 42)
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  Language Area  Organizedaround the lateral fissure.  Broca’s area: concerned with expressive aspects of language.  Wernick’s area: responsible for comprehension of the spoken words.  Nearby regions of temporal lobe and parietal lobe (angular gyrus & supramarginal gyrus of the inferior parietal lobule) are important in naming, reading, writing, and calculation.
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  White Matter  Underliesthe cortex, contains nerve fibers, neuroglia cells and blood vessels.  The nerve fibers originate, terminate or sometimes both, within the cortex.  Depending on their origin & termination, these nerve fibers are classified into three types: Association, Projection & Commissural Association fibers: Unite different parts of the same hemisphere, are of two types: long & short Commissural fibers: Connect the corresponding regions of the two hemispheres Projection fibers: Consist of afferent and efferent fibers of the cerebral cortex