The New Childrens Encyclopedia

280

Think! Act!

Your brain is a complex organ. It’s a bit like a big

computer but more adaptable. It controls all you

do. It makes you think. It allows you to learn.

It stores your memories. It makes you who you are.

WHAT IS YOUR BRAIN?

Your brain is a collection of about a

hundred billion nerve cells called neurons.

These are linked to each other and they

share and pass information all day and

all night throughout your life.

Message transfer Messages

constantly arrive in your

brain from your body, sent in

the form of electrical signals

along nerves. Your brain

processes those messages and

sends out instructions telling

your body what to do.

The spinal

cord is as

thick as your

little finger.

CENTRAL NERVOUS SYSTEM (CNS)

A bundle of nerves called the spinal cord runs from

the brain down your back, protected inside a column

of bones, the backbone. The brain and spinal cord

form your central nervous system.

 THE SPINAL CORD

transports information from the

brain to the rest of the body and

back via pairs of spinal nerves.

Spinal nerve

The central nervous

system allows you to

make voluntary actions

such as eating, reading,

and walking, as well as

controlling many actions

itself. For example, you aren’t

aware of the muscles working

in your stomach—they

work automatically.

Cross-section

of spinal cord

 FITTING TOGETHER

This model shows how the brain,

spinal cord, and eyes link up.

Your brain has a joke center,

which allows you to understand why a

joke is funny. This means that some

people with damage to the front of their

brains, (particularly on the right-hand

side) just don’t find jokes funny. Given

a joke with a choice of different

punchlines, they can’t tell which

is the funny one.

O
 An adult brain weighs about 2 lb 9 oz

(1.3 kg).

O
 Signals travel along neurons at about

250 mph (400 km/h).

O
 80 percent of your brain is water.

O
 Your brain uses about 20 percent of

your energy.

FAST FACTS

THE HUMAN BODY

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