200008.vtt
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WEBVTT
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The brain is composed of more than a thousand billion neurons.
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Specific groups of them, working in concert,
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provide us with the capacity to reason, to
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experience feelings, and to understand the world.
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They also give us the capacity to remember
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numerous pieces of information.
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There are three major components of the brain.
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The cerebrum is the largest component,
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extending across the top of the head down to ear level.
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The cerebellum is smaller than the cerebrum and located underneath it,
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behind the ears toward the back of the head.
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The brain stem is the smallest and
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is located under the cerebellum,
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extending downward and back toward the neck.
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The cerebral cortex is the outside portion of the
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cerebrum, also called the “gray matter”.
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It generates the most complex intellectual
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thoughts and controls body movement.
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The cerebrum is divided into left and right sides,
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which communicate with each other through a thin stalk of nerve fibers.
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The grooves and folds increase the cerebrum’s surface area,
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allowing us to have a tremendous amount of gray matter inside of the skull.
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Here, the left side of the brain is highlighted
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to show the control over right arm and leg movement,
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and the right side of the brain is highlighted
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to show the control over left arm and leg movement.
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The left side of the brain controls the muscles
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on the right side of the body and vice versa.
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Voluntary body movements are controlled
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by a region of the frontal lobe.
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The frontal lobe is also
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where we shape
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emotional reactions and expressions.
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There are two parietal lobes,
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one on each side of the brain.
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The parietal lobes are located behind the frontal lobe towards
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the back of the head and above the ears.
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The taste center is located in the parietal lobes.
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All sounds are processed in the temporal lobe.
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They are also important for learning,
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memory, and emotion.
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The occipital lobe is located at the back of the
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head behind the parietal and temporal lobes.
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The occipital lobe analyzes visual information from
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the retina and then processes that information.
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If the occipital lobe becomes damaged, a person could become blind,
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even if his or her eyes continue to function normally.
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The cerebellum is located at the back of the head
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underneath the occipital and temporal lobes.
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The cerebellum creates automatic programs
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so we can make complex movements without thinking.
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The brain stem is located underneath the temporal lobes
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and extended down to the spinal cord.
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It is critical for survival because it connects the brain with the spinal cord.
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The top portion of the brainstem is called the midbrain.
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The midbrain is a small portion of the brain
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stem located at the top of the brain stem.
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Just below the midbrain is the pons,
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and below the pons is the medulla.
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The medulla is the part of the brain stem closest to the spinal cord.
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The medulla, with its critical functions,
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lies deep within the head, where it is well-protected
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from injuries by an extra-thick section of overlying skull.
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When we are asleep or unconscious, our heart rate, breathing
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and blood pressure continue to function because they’re regulated by the medulla.
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And that concludes a general overview of the components of the brain.