The Nervous System
The Nervous System
What is its FUNCTION?
• Receives information
about what’s happening
inside and outside the
body.
• Directs the way your
body responds to this
info.
• Helps maintain
homeostasis.
The Nervous System (Central)
The nervous system is
made up of the:
• Brain (controls most
functions of the body)
• Spinal Cord (a thick
column of nerve tissue that
links the brain to most of
the nerves in the periphal
nervous system)
• Network of Nerves that
The Brain
-About 3 pounds
-Size of both
hands together
Interprets input from senses,
controls the movement of
skeletal muscles, and carries
out mental processes such
as learning, remembering,
and making judgments.
-2 halves (left
and right)
-Different parts
of the brain do
different things
Brain Stemcontrols
involuntary
actions
Cerebrum
Cerebellumcoordinates
actions of
your muscles
and helps yo
keep your
balance
A Neuron (Nerve Cell)
AXON
AXON
TIPS
DENDRITES CELL
BODY
Neurons carry information through the nervous system.
There are BILLIONS of neurons in your body.
They are constantly sending/receiving messages.
A Neuron (Nerve Cell)
AXON
AXON
TIPS
DENDRITES CELL
BODY
Direction message travels
AXON – carries the messages
down to the AXON TIPS,
which sends the message to
the next neuron.
DENDRITES – receive
messages and sends
them toward CELL
BODY.
Let’s act it out….
AXON
AXON
TIPS
DENDRITES CELL
BODY
What happens in your nervous system
when you are stung by a bee?
The Nervous System
& our Senses
Let’s
test our
Nervous
systems…
Test Your Reaction Time
How fast do messages travel in your nervous
system?
You will time how long it takes a message to
travel from your EYES to your BRAIN to
your HAND.
Can we make the messages travel faster?
Test your Reaction Time
May 5, 2009
Question: How long will it take for a nerve
signal to travel from your EYES to your
BRAIN to your HAND?
Hypothesis:(Make a prediction!)
Observations & Data Collection:
(Paste your data table into your notebook)
Conclusion Question: What happens to
your reaction time as your practice?
Explain. (Answer the question in your notebook).
Test Your Reaction Time
1) Hold your thumb and
fingers about 3 cm
apart at the 0 cm end
of a meter stick.
2) Your partner will drop
the meter stick and
you need to grab it as
quickly as possible.
3) The faster you grab it,
the lower the
measurement on the
meter stick.
Test Your Reaction Time
4) Use the measurement
on the meter stick to
look up your reaction
time in the table.
5) Repeat the
experiment 3-4
times.
6) What happens to
your reaction time as
you practice?
The Sense Organs
Your sense organs have nerve
receptors that respond to
stimuli (stuff outside the
body) and send messages to
your brain where it is
interpreted.
EYES responds to LIGHT
EARS responds to SOUND
SKIN responds to TOUCH
NOSE responds to SMELL
TONGUE responds to TASTE
Taste
• Taste works like your
other senses.
• Nerve receptors (your
taste buds) recognize
different chemicals in
your food.
• The taste buds send
the chemical information
to your brain, where it is
recognized as taste.
Tongue Taste Mapping
• How do you taste
different flavors?
• Can certain tastes be
detected better on
certain parts of the
tongue?
• You will test four
different flavors to see
where on the tongue
they are strongest.
Tongue Taste Mapping
• You will have four
different flavors to
taste:
• Salty (chicken broth)
• Sour (lemon juice)
• Bitter (tonic water)
• Sweet (kool-aid)
Tongue Taste Mapping
May 12, 2009
Question: Can certain tastes be detected
better on certain parts of the tongue?
Where do you detect sweet, salty, bitter
and sour?
Hypothesis:(Make a prediction! What part of the
tongue tastes Sweet? Sour? Salty? Bitter?
Observations & Data Collection:
(Paste your diagram into your notebook)
Tongue Taste Mapping
• Use your Q-tip to dab
each liquid on each part
of your tongue (the tip,
sides, middle, and
back).
• Label your tongue
diagram where you
taste:
•SOUR
•BITTER
SWEET
SALTY
Today, you will dissect an eyeball!
Extra Time?
Let’s check out the
Senses Challenge
How does the eye see?