Brain Anatomy
By: Nick V.
Neurons
Your brain is full of billions of microscopic
cells. Many of these cells are special
messengers called neurons. Neuron means
"nerve cell." We have about 100 billion
neurons in our body. To picture the size of
a neuron, think about the fact that
30,000 neurons can fit on the head of a
pin! Neurons carry special signals back and
forth throughout your body. Billions of
neurons are chained together in a network
of nerves. Nerves are a large amounts of
neurons linked together in a small place. Your nerves send tiny electronic signals
through your body to the brain stem and to the main brain.
The neurons inside your brain have three basic parts. Every tiny neuron consists of
a cell body, an axon, and a dendrite. Neurons "talk" to each other by sending
chemicals to each other across a very tiny space called a synapse. Learning happens
when two neurons "talk" to each other. As the brain makes connections, it actually
grows dendrites and makes stronger synapses. That means that the more you learn,
the heavier your brain gets! So that means you really can "grow" a better brain.
Do people lose brain cells as they get older? Yes, you lose brain cells every day
because of decay and disuse. Scientists aren't sure how many you lose each day but
you don't need to worry. You have enough to last for your whole lifetime.
Some people think that your brain can never grow new neurons. That isn't true.
Scientists have found that one area of the brain called the hippocampus can grow
new neurons. They are doing more research to see if there are other areas of the
brain that regenerate neurons.
Glial Cells
You've probably never heard of a glial cell. That's because when people talk about
brain cells, they usually only think of neurons. But did you know that without glial
cells your the neurons wouldn't work? So without glial cells we wouldn't have
working neurons, and without neurons there would be no point of glial cells. About
90 percent of your brain cells are glial cells (the other 10 percent are neurons)
which means that we have about 1,000 billion of them. Did you know that glial
means "glue?" These cells are called glial or "glue" because they act like little ropes
for neurons to hold on to when the brain is being formed. Otherwise, scientists
think they act like housekeepers for neurons. Glial cells attach themselves to
neurons and feed them. Unlike neurons, they are able to reproduce, so your brain
can make as many as it needs.
Do you know what famous scientist had a whole lot of glial cells in his brain? The
answer is Albert Einstein. The scientists who studied his brain found a huge
number of glial cells in a specific area of his brain. The scientists think this means
that this area of Einstein's brain showed more use than the same area in any other
brain ever studied.
Here is a table of some other parts of the brain you might be interested in
learning more about:
Part
The Cerebral
Cortex
Part
Cerebellum
Part
Location
This newspaper sized
"white matter" is the
1/4" outside covering
of both brain
hemispheres.
Location
The cerebellum is a
cauliflower-shaped
structure located in
the lower part of the
brain next to the
occipital area and the
brain stem.
Location
Functions
The cerebral cortex
controls your thinking,
voluntary movements,
language, reasoning,
and perception.
Functions
The cerebellum
controls your
movement, balance,
posture, and
coordination. New
research has also
linked it to thinking,
novelty, and emotions.
Functions
Other Facts
In higher mammals the
cortex looks like it has
lots of wrinkles,
grooves and bumps.
Grooves and bumps are
also called "gyros."
Cortex is the Latin
word for "bark."
Other Facts
The very word
cerebellum comes from
the Latin word "little
brain."
Other Facts
Hypothalamus
The hypothalamus is
part of the limbic
system. It is located in
the internal portion of
the brain under the
thalamus.
The hypothalamus
controls your body
temperature, emotions,
hunger, thirst,
appetite, digestion and
sleep.
The hypothalamus is
composed of several
different areas and is
located at the base of
the brain. It is only
the size of a pea
(about 1/300 of the
total brain weight), but
is responsible for some
very important
behaviors.
Part
Location
Functions
Other Facts
Thalamus
The thalamus is part
of the limbic system so
it is located in the
internal portion of the
brain or the center of
the brain.
Part
Location
Pituitary Gland
Part
Pineal Gland
Part
The pituitary gland is
part of the limbic
system although it
hangs below the rest
of the limbic system.
Location
The thalamus controls
your sensory
integration and motor
integration.
Functions
The pituitary gland
controls your
hormones and it helps
to turn food to energy.
Functions
The pineal gland is part The pineal gland
of the limbic system so controls your growing
it is located in the
and maturing.
internal portion of the
brain.
Location
Functions
The thalamus receives
sensory information
and relays it to the
cerebral cortex. The
cerebral cortex also
sends information to
the thalamus which
then transmits this
information to other
parts of the brain and
the brain stem.
Other Facts
Without your pituitary
gland, you could eat
but you wouldn't get
any energy from the
food.
Other Facts
I bet you didn't know
that your pineal gland
is activated by light so
if you were born and
lived all your life in a
place without a trace
of light your pineal
gland would never
start to work.
Other Facts
Amygdala
The almond shaped
amygdala is part of the
limbic system so it is
located in the internal
portion of the brain.
Part
Location
Hippocampus
Part
Mid-brain
The crescent shaped
hippocampus is found
deep in the temporal
lobe, in the front of
the limbic system.
Location
The mid-brain is an
area located in the
middle of the brain
behind the frontal
lobes.
The amygdala (there
are two of them)
control your emotions
such as regulating
when you're happy or
mad.
Your amygdala is very
important. Without it
you could win the
lottery and feel
nothing. You wouldn't
be happy.
Functions
The hippocampus
forms and stores your
memories (scientists
think there are other
things unknown about
the hippocampas) and
is involved in learning.
Other Facts
Your hippocampus is
one of the most
important parts of
your brain. If you
didn't have it, you
wouldn't be able to
remember anything.
People with
Alzheimer's Disease
loose the functioning
of their hippocampas.
Functions
The mid-brain controls
your breathing,
reflexes, and your
swallowing reflexes.
Other Facts
The mid-brain includes
the thalamus,
hippocampus, and
amygdala. Every living
thing has to have a
mid-brain.
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