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Basic Organization of the Nervous System

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The Nervous System
  • Central Nervous System (CNS)
    • consists of the brain and spinal cord
    • the main control center
  • Peripheral Nervous System (PNS)
    • consists of the nerves branching off from the brain and spinal cord
    • allows the CNS to communicate with the rest of the body
    • consists of the sensory division and the motor division

Peripheral Nervous System
  • Sensory Division
    • also known as the afferent division
    • picks up sensory stimuli
    • transmits signals from the body to the brain
  • Motor Division
    • also known as the efferent division
    • sends directions from the brain to effector organs and glands
    • transmits signals from the brain to the body
    • consists of the somatic and autonomic nervous system
Motor Division
  • Somatic Nervous System
    • voluntary ⇒ skeletal muscle movement
  • Autonomic Nervous System
    • involuntary ⇒ internal organs
    • example: heartbeat, lungs, stomach
    • consists of the sympathetic and parasympathetic nervous system
Autonomic Nervous System
  • Sympathetic Nervous System
    • "fight or flight"
    • increases heart rate
    • dilates bronchioles for increases respiration
    • dilates pupils
    • secretes epinephrine and norepinephrine from the adrenal glands
    • inhibits digestion
    • relaxes bladder
  • Parasympathetic Nervous System
    • "rest and digest"
    • decreases heart rate
    • constricts bronchioles
    • constricts pupils
    • secretes acetylcholine
    • stimulates digestion
    • contracts bladder
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