Cerebrum
The cerebrum is the large cranial portion of the brain also called the telencephalon. A dorsal view of the brain reveals the 2 prominent cerebral hemispheres which are separated by the longitudinal cerebral fissure.
The 2 hemispheres are connected by the corpus callosum .
Tissues of the hemispheres are made up of grey and white matter.
There are 3 general locations of grey matter:
1. Cerebral Cortex – the surface layer of the hemisphere, makes up about 1/2 the volume of the brain. The cortex is divided into 4 lobes: frontal, parietal, temporal & occipital. Frontal lobe – largest, most cranial part of hemisphere, lie deep to the frontal bones. Parietal lobe – caudal to the frontal lobes, deep to the parietal bones. Temporal – lateral aspect of the brain, lying ventral to the frontal lobes, deep to the temporal bones. Occipital lobe – makes up the caudal aspect of the hemisphere, lies on the tentorium cerebelli. 2. Basal Nuclei- beneath the cerebral cortex and is responsible for the smooth execution of motor activity and maintenance of muscle tone. 3. The Limbic system within the cerebrum helps to control emotions, motivation and is a pleasure centre.
Lying below the cerebral cortex is the white matter. This is primarily composed of myelinated axons in 3 types of tracts:
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