Brains

The brain is the body`s main command post. No matter what a person does, the brain directs everything.
It constantly receives signals from all the sense organs: the ears, eyes, nose, tongue and skin. And it responds by sending messages to your legs, arms, fingers,eyelids, waist and shoulders – in other words, to all the parts of your body.
Without the help of your brain, you could not move, see, hear, speak or read. You could not think. You could not even breathe or digest your food.
The human brain is an extremely complex structure. Its outer layer, the cerebral cortex, is only about two or three centimeters thick. But it is made up of fifteen billion special nerve cells. There are more cells in the brain than people on the earth!
The brain cells work in small groups, and each has its particular function. Some groups are able to receive sounds, others respond to odors. Still others can distinguish colors. There are cell groups which listen to the work of the heart. Some make sure the lungs are breathing deeply enough.…