Brain : Brainstem
The brain is the supervisory center of the nervous system consisting of grey matter (superficial parts called cortex and deep brain nuclei) and white matter (deep parts except the brain nuclei). It controls and coordinates behavior, homeostasis (body functions such as heartbeat, blood pressure, fluid balance, and body temperature) and mental functions (such as cognition, emotion, memory and learning).Although the brain is usually referred to as the supervisory center of vertebrates, the same term can also be used for the invertebrate central nervous system.
The vertebrate brain can be subdivided as follows:
- medulla oblongata (brain stem)
- myelencephalon[?]
- metencephalon[?] (midbrain[?])
- diencephalon[?]
- telencephalon[?] (cerebrum[?])
The cerebrum[?] and the cerebellum consist each of two halves (hemispheres). The corpus callosum[?] connects the two hemispheres of the cerebrum.
In most vertebrates the metencephalon[?] is the highest integration center in the brain, whereas in mammals this role has been adopted by the telencephalon[?]. Therefore the cerebrum is the largest section of the mammalian brain and its surface has many deep fissures (sulci) and grooves (gyri), giving an excessively wrinkled appearance to the brain.
See cephalic disorders for information on congenital development disorders relating to the brain.
The adult human brain usually weighs about 1 - 1.5 kilograms in an average volume of 1,600 cubic centimetres. The intelligence of the individual isn't necessarily related with the weight of the brain, but with the efficiency and number of connections between cells.
The blood supply to the brain involves several arteries that enter the brain and communicate in a circle called the circle of Willis. Blood is then drained from the brain through a network of sinuses[?] that drain into the right and left internal jugular veins[?].
During many past millennia, the function of the brain was unknown. Ancient Egyptians threw the brain away prior to the process of mummification. Ancient thinkers such as Aristotle imagined that mental activity took place in the heart. The Alexandrian biologists Herophilus and Erasistratus[?] were among the first to conclude that the brain was the seat of intelligence. Galen's theory that the brain's cavities, or ventricles, were the sites of thought and emotion prevailed until the work of the Renassiance anatomist Vesalius.
Brain is also the name of a commune in the Côte-d'Or département in France.
And nine long serpents twist
A riotously beautiful design
Of eloquent spirals, fair and fine,
Seemingly free, yet tangled in that living vine.
And in this chest shall be
Enough to hold all memory
And this shall be the place
Our bodies, and obliterate the trace
Of night.html">night...
Are dead, and lose the key!
The Pedlar
Hark, people, to the cry
Seeking a golden bowl!
He wanders through the city
For all the ancient metal
In the dim, dusty attic
Of your soul.
He refuses nothing--
Which may have played their part
For ten of these he will give
Once guarding hearth-fires of content,
In an obscure corner,
A new tin tea-kettle
Fashioned to hold
O woman, if acid reveal
He will gladly give you
His young, white body--
If not,
And a bright tin sieve
And roses.
Portrait of a Lady in Bed
I. THE COVERLET
My cowardice
From everything...
From cold, which makes me yield
Beneath the snow;
From heat, which makes me faint
And I shall die of fright
Yes, most of all from love.html">love.
How can love touch me?
Or cold,
Safely
Sustains my Spirit
Is wine, banishing sleep!)
Your thoughts of me are feathers,
Drifting, dancing,
Blown by a breath of fancy
They would blind me
If I dared see them;
And to know that you think of me
Through the night.
III. SOUVENIR
Harlequin, seeing me gay.html">gay
For fools need mirth,
O solemn Harlequin!
Tall tragedians make me laugh
Tall, dark villains, and heroes with blonde hair
(I could elope with a tragedian!)
But you with your clowning, Harlequin,
But I could not make you gay!
.
On
wordlookup.net
All is still licensed under the GNU FDL.
It uses material from the wikipedia.
|
|