The Nervous System

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The Nervous System
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Key Concepts

• Know the function and divisions of the nervous
  system (CNS PNS)
• Describe the structure of a neuron
• Identify and know the function of the three types
  of neurons and the describe neurotransmission
• Know the main parts of the brain and explain
  their functions
• Identify the lobes of the cerebral cortex

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Funtion of the Nervous System

• Receive information externally and internally
• Respond to stimuli
• Maintain stable internal conditions.

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Neurons

• Neurons are the cells that carry nerve impulses
  through your nervous system
• There are 3 kinds of neurons
• Interneuron -connects motor and sensory neurons
  what the brain is mostly made of
• Sensory picks up stimuli from internal and
  external sources
• Motor sends message to muscle to produce an
  action or movement

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Neuron Structure

• A neuron is made up of 3 main parts
• Cell body where the nucleus and organelles are
  found
• Dendrites extensions that pick up nerve
  impulses and carry to the cell body
• Axon carries the nerve impulse away from the
  cell body and to another neuron
• Nerve impulses travel in only ONE direction

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Neurotransmission

1. Message travels form the dendrites through the
   cell body and to the end of the axon.
2. The message causes chemicals, neurotransmitters,
   to be released from the end of the axon into the
   space between the axon of one neuron and the
   dendrites of another
3. The neurotransmitters then travel across the
   synapse on the receptors on the dendrites of
   another neuron.
4. Once the neurotransmitters have attached to the
   receptors the impulse is passed on.
5. The neurotransmitters are released from the
   receptors.

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Divisions of the Nervous System

• Central Nervous System (CNS)
• Brain
• Spinal cord
• Peripheral Nervous System (PNS)
• All of the nerves located OUTSIDE of the CNS
  (senses)

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Main Parts of the Brain

• Cerebrum
• Cerebellum
• Brain Stem

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Peripheral Nervous System

• Consists of a network of nerves that branch out
  from the CNS.
• Somatic system control voluntary actions
• Autonomic system controls involuntary actions

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Reflex

• Automatic response that occurs very rapidly
  without conscious control
• Nerve impulse goes to spinal cord but NOT the
  brain helps to speed up the reaction