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INFORMATION - BRAIN - THE HUMAN BRAIN-6
STRUCTURES OF BRAIN
CEREBRUM
The major part of the brain is called the Cerebrum.
Some times when you talk about the brain, you are talking about the cerebrum.
CEREBRAL HEMISPHERES
It is divided into two major parts:
1. The Right Cerebral Hemisphere, and
2. The Left Cerebral Hemisphere.
A big groove separates these two hemispheres. This groove is called the Great Longitudinal Fissure.
The Falx, the special fold of the Dura mater, stays here.
CORPUS CALLOSUM
The two hemispheres of the brain are connected at the bottom by a structure called the Corpus Callosum.
The corpus callosum not only joins the two halves of the brain but delivers messages from one half of the brain to the other half.
CEREBRAL CORTEX
GRAY MATTER
The surface of the cerebrum contains billions of neurons and glia. It is known as the Cerebral Cortex. The cerebral cortex appears grayish brown in color. It is called "Gray Matter". Also, the surface of the brain appears wrinkled.
The cerebral cortex has small grooves called 'Sulci', larger grooves called 'Fissures' and bulges between the grooves called 'Gyri'.
These bulges and grooves have specific names which also serves as landmarks. Different regions of the brain as specific functions.
WHITE MATTER
The gray matter of the cerebral cortex has lots and lots of neurons. These are connected by fibers, which run beneath the cerebral cortex. This portion of the brain appears white in color so it is known as "White Matter".
LOBES
The cerebral hemispheres are further divided into different lobes by several distinct fissures on its surface. Lobes are simply broad regions of the brain.
These lobes are: Frontal, Parietal, Occipital, and Temporal on each hemisphere.
Each lobe is further divided into different areas that serve very specific functions.
Although the brain is divided into different hemispheres, lobes and areas; they do not function alone. It looks like they have great communication system among them. So that the brain functions as a whole.
Like computer, messages within the brain are delivered in many different ways. There are different pathways. Messages can travel from one gyri to another, from one lobe to another, from one side of the brain to the other, from one lobe to the deeper structures of the brain, from deep structures to another region in the central nervous system. and from the central nervous system to peripheral nervous system to the target organs.
Specific areas of the brain are in contact with specific areas of different parts of the body. In other way different areas of different parts of the body are represented by specific areas of the brain. That is why, when you electrically stimulate specific region in the brain, it will cause movement or sensation to occur in a very specific part of the body. These connections are just like electric wiring and circuits.
It is interesting to know that one side of the brain controls the opposite side of the body. This is because the wires connecting them and passing information, cross the midline at different levels in the brain and the spinal cord.
Some believe that one of the two hemispheres is dominant. Is it true?
The next generation will give the answer!
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