1. The Nervous System

2. 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.

3. 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

4. The Brain Cerebrum 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.
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

5. A Neuron (Nerve Cell)
AXON
DENDRITES
CELL BODY
AXON TIPS
Neurons carry information through the nervous system.
There are BILLIONS of neurons in your body.
They are constantly sending/receiving messages.

6. Direction message travels
A Neuron (Nerve Cell)
AXON
DENDRITES
CELL BODY
AXON TIPS
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.

7. What happens in your nervous system when you are stung by a bee?
Let’s act it out….
AXON
DENDRITES
CELL BODY
AXON TIPS
What happens in your nervous system when you are stung by a bee?

8. The Nervous System & our Senses

9. Let’s test our Nervous systems…

10. 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?

11. Hypothesis:(Make a prediction!)
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).

12. Test Your Reaction Time
Hold your thumb and fingers about 3 cm apart at the 0 cm end of a meter stick.
Your partner will drop the meter stick and you need to grab it as quickly as possible.
The faster you grab it, the lower the measurement on the meter stick.

13. 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?

14. 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

15. 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.

16. 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.

17. Tongue Taste Mapping You will have four different flavors to taste:
Salty (chicken broth)
Sour (lemon juice)
Bitter (tonic water)
Sweet (kool-aid)

18. Observations & Data Collection:
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)

19. Tongue Taste Mapping Label your tongue diagram where you taste:
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

20. Today, you will dissect an eyeball!

21. Extra Time?
Let’s check out the
Senses Challenge

22. How does the eye see?