Unit 10 Chapter 36 The Nervous System

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Unit 10Chapter 36The Nervous System
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The Nervous System

• Neurons
• Nerves cells, the basic unit of structure
  function of the nervous system

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The Nervous System

• Neuron structure
• Dendrites
• Branchlike extensions that receive impulses
  carry them toward the cell body
• Cell body
• Location of the nucleus much of the cytoplasm
• Axons
• Extensions carrying the impulse away from the
  cell body

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The Nervous System

• Categories of neurons
• Sensory neurons carry impulses from the body to
  the spinal cord brain
• Motor neurons carry impulses from the spinal cord
  brain to the body
• Interneurons are found within the spinal cord
  brain, pass response impulses between sensory
  motor

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The Nervous System

• Transmitting an Impulse
• Each impulse consists of an electrical charge
  that travels the length of a neurons cell
  membrane to a gap, called a synapse
• The impulse is caused by the depolarization of
  chemicals surrounding the cell membrane
• Chemicals called nuerotransmitters, are released
  into the synapse, which stimulates a charge in
  the next neuron

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Transmitting an impulse along the axon
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Transferring signals across the synapse to an
adjoining neuron
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The Nervous System

• Division of the Nervous System
• Central Nervous System (CNS)
• Consists of the
  brain and spinal cord
• Peripheral Nervous
  System (PNS)
• Consists of the nerves
  that carry messages
  to from the CNS

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The Central Nervous System

• Anatomy of the Brain
• Cerebrum
• Largest lobe, controlling voluntary movement,
  intelligence, memory, the senses
• Cerebellum
• Located at the back,
  controlling balance, posture, and
  coordination
• Medulla oblongata
• Located within the brain stem,
  controlling involuntary (vital) activities

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Cerebrum
Cerebellum
Medulla
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The Peripheral Nervous System

• Somatic Nervous System (SNS)
• Made up of cranial spinal nerves, relaying
  voluntary information between the CNS and the
  skin muscles
• Autonomic Nervous System (ANS)
• Made up of the sympathetic parasympathetic
  systems, relaying involuntary responses, not
  under conscious control

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The Peripheral Nervous System

• Reflexes
• An automatic, unconscious response for protecting
  the body
• This response travels to the spinal cord where
  it responds directly back to a muscle

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The Senses

• Sensing Chemicals
• Odor chemicals stimulate nerve endings in the
  nasal passages, which transmit through the
  olfactory nerve to the cerebrum
• Chemical dissolved in saliva stimulate
  nerve endings in the taste
  buds of your tongue,
  detecting only sweet,
  sour, bitter salty

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The Senses

• Sensing light
• The eyes retina contains nerve enedings called
  rods cones, which transmit impulses through the
  optic nerve to the cerebellum

Rods and Cones
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The eye
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The Senses

• Sensing vibrations (sound)
• Sounds waves vibrates the eardrum, the three
  small boneshammer, anvil, stirrupthen the
  nerve endings in the cochlea, which transmit
  impulses through the auditory nerve to the
  cerebrum

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The ear
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The Senses

• Sense of Balance
• Within the inner ear are three semicircular
  canals, which contain fluid nerve endings that
  transmit impulses to the cerebellum

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The Senses

• Sense of Touch
• Nerve endings in the dermis of your skin respond
  to temperature, pressure and pain, transmitting
  impulses through sensory neurons to the CNS