The Nervous System

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The Nervous System
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Main parts of the nervous system

• THE BRAIN is the center of the nervous system
• Your nervous system is a system of nerve cells
  that connect your brain with every part of your
  body
• THE SPINAL CORD is the main nerve of your body.
  31 pairs of nerves branch out from your spinal
  cord

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JOBS of nervous system

• Sends messages from the brain to the rest of the
  body along nerve cells (neurons)
• You taste, hear, and smell with your brain
• Sensory nerve cells in your body send signals to
  your brain
• Your brain sorts these messages and tells you
  what you are seeing, hearing, tasting, smelling,
  or feeling

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More about the neurons

• They are also called neurons
• Your brain has about one trillion neurons
• Your spinal cord has one billion neurons
• Neurons collect, receive, and send information
  very quickly around your body
• They are found throughout your body-eyes, ears,
  mouth, nose, skin, muscles, joints..

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Dendrites and Axons

• Short twig like fibers
• They receive nerve signals and send them into the
  bodies of nerve cells
• These signals leave the cells on longer fibers
  called axons
• Axons transmit information from one neuron to
  another

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MORE ABOUT THE BRAIN

• There are 3 parts of the brain
• The cerebellum- controls coordination and complex
  movements of your muscles (like playing sports)
• Cerebrum- largest part of brain. Controls your
  ability to think, learn, remember
• Brain stem- Control important life processes that
  take place in your body (attention, arousal, and
  consciousness) All info passes thru here on way
  to brain

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Interesting facts about brain

• The right half of the brain controls the movement
  on the left side of your body
• The left half controls the right side of your
  body
• Weight 1300-1400 grams or 3 lbs (as adult)
• Weight 350-400 grams (as infant)
• Unconsciousness will occur after 8-10 seconds
  after loss of blood supply to the brain.
• The world record for time without sleep is 264
  hours (11 days) by Randy Gardner in 1965

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Interesting facts about spinal cord

• Length of human spinal cord is 43-45 cm
• Weight is 35 grams
• 31 spinal nerves

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SPINAL CORD