messages from your five senses, too. Different areas handle sights,
sounds, tastes, smells, and touch.
Name
Friday, June 8
The Brain
By Sharon Fabian
That three-pound pinkish-gray blob in
your head may be ugly but it can do a lot
of things. Like a computer, it can figure
out math problems, and store and
organize information. Like a camera, it
can turn patterns of light into pictures. It
can also regulate body processes,
produce emotions, understand and
construct language, and order muscles to
move.
If your nervous system, which includes your brain, is the control
center for your body, then your brain is its commander-in-chief.
Your brain has three main parts: the large part called the cerebrum,
the smaller part in the back called the cerebellum, and the brain stem
which attaches the brain to the spinal cord. The large part, the
cerebrum, is made up of layers of folds and wrinkles called the
cerebral cortex. As the surface of your brain grows, it folds and
wrinkles more to fit into its space in your skull. Somewhere between
10 billion and 100 billion nerve cells are at work in your brain. They
are powered by the food that you eat and the oxygen that you breathe.
In case of a fall, or a blow to the head, your brain is protected by your
cranium, also called your skull, and by three protective layers called
meninges inside your skull.
Your brain has specialized parts for particular jobs, but some jobs
involve many different parts of the brain. Reading is a good example.
When you read a word, the light that enters your eyes is seen as an
image of the word in the vision center of your brain. Another part of
your brain transforms that picture into the right sound pattern for the
word. Another part figures out the meaning of the word. If you want
to say the word aloud, the message is sent to yet another area that
instructs the muscles of your throat and mouth to make the right
sounds.
Your brain has specialized areas in its cerebral cortex to receive
The cerebral cortex, along with another part, the cerebellum, controls
movements of your muscles. In the area called the motor cortex, a
particular section connects to each part of your muscular system.
There is a section for your fingers, a section for your wrist, a section
for your arm, a section for your toes, and so on. The body parts that
do the most complicated movements get the most brain space. That is
why the muscles of the mouth and tongue have a big space on the
brain, because they have to make many different movements to speak
and eat.
Your brain stem has parts that regulate automatic body processes.
Your heartbeat and your breathing are regulated by the brain stem.
A part called the limbic system, which spreads over several parts of
the brain, is in charge of emotions. When a horror movie scares you,
or a hug makes you feel happy, somehow the limbic system is
involved.
Thinking and remembering are really complicated things that the
brain does. Scientists have only begun to figure them out. They know
that it has something to do with the brain building new connections
between its nerves.
The brain is not easy for scientists to study, since they can't just take
a look in there. But they do have some ways of finding out what's
happening inside. By studying people who have had brain injuries,
they can learn which parts of the brain do which jobs. They can record
brain activity with a machine hooked up to electrodes fastened to the
outside of a person's skull. Intelligence tests, and other types of tests,
also provide information about what knowledge is inside the brain.
When scientists learn some new facts about the brain, they often come
up with just as many new questions. Now that you know a few facts
about the brain, maybe you have some new questions too.
Name
Friday, June 8
The Brain
Questions
1. Your brain is the main part of your ______ system.
A. digestive
B. skeletal
C. respiratory
D. nervous
2. Reading involves ______ of the brain.
A. many parts
B. no parts
C. two parts
D. one part
3. The wrinkles and folds of the cortex make up which part of the
brain?
A. brain stem
B. cerebellum
C. cranium
D. cerebrum
4. Cranium is another word for the ______.
A. brain
B. cerebrum
C. skull
D. spine
5. Heartbeat and breathing are examples of ______.
A. brain activities
B. resting activities
C. voluntary activities
D. automatic activities
6. Scientists can learn about what different parts of the brain do
by studying ______.
A. people who have had a brain injury
B. report cards
C. intelligence tests
D. electrodes
7. Scientists now understand how all parts of the brain work.
A. true
B. false
8. Meninges are three more layers inside the skull that help
protect the brain.
A. false
B. true