The Nervous System

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The Nervous System
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The Nervous System

• What is its FUNCTION?
• Receives information
• about whats happening
• inside and outside the
• body.
• Directs the way your
• body responds to this
• info.
• Helps maintain
• homeostasis.

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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
• branch out to ALL parts
• of your body

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The Brain
Interprets input from senses, controls the
movement of skeletal muscles, and carries out
mental processes such as learning, remembering,
and making judgments.
Cerebrum

• About 3 pounds
• Size of both hands together
• 2 halves (left and right)
• Different parts of the brain do different things

Cerebellum-coordinates actions of your muscles
and helps you keep your balance
Brain Stem-controls involuntary actions
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A Neuron (Nerve Cell)

• Neurons carry information through the nervous
  system.
• There are BILLIONS of neurons in your body.
• They are constantly sending/receiving messages.

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A Neuron (Nerve Cell)
Direction message travels

• DENDRITES receive messages and sends them
  toward CELL BODY.

• AXON carries the messages down to the AXON
  TIPS, which sends the message to the next neuron.

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Lets act it out.

• What happens in your nervous system when you are
  stung by a bee?

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The Nervous System our Senses
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Lets test our Nervous systems
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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?

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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).
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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.

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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?
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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

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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.

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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.

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Tongue Taste Mapping

• You will have four different flavors to taste
• Salty (chicken broth)
• Sour (lemon juice)
• Bitter (tonic water)
• Sweet (kool-aid)

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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)
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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 SWEET
• BITTER SALTY

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Today, you will dissect an eyeball!
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Extra Time?

• Lets check out the
• Senses Challenge

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How does the eye see?
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