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Divisions of the Nervous System

May 28, 2024

Divisions of the Nervous System

Major Divisions

  • Central Nervous System (CNS)
    • Comprised of the brain and spinal cord.
  • Peripheral Nervous System (PNS)
    • Consists of nerves running throughout the body.

Subdivisions of the Peripheral Nervous System

  • Somatic Nervous System

    • Carries sensory signals from the body to the CNS.
    • Carries motor signals from the CNS to skeletal muscles.
    • Associated with voluntary movement.
    • Example: Clicking a video involves a signal from the brain to the finger.
  • Autonomic Nervous System (ANS)

    • Sometimes called the involuntary nervous system.
    • Regulates the internal environment of the body.
    • Carries signals between internal organs and the CNS.
    • Involved in regulating functions like digestion and heartbeat.

Subdivisions of the Autonomic Nervous System

  • Sympathetic Nervous System

    • Stimulates and mobilizes energy resources.
    • Involved in fight or flight responses.
    • Example: Increases heart rate, blood pressure, and stimulates sweat glands during frightening situations.
  • Parasympathetic Nervous System

    • Conserves energy.
    • Involved in rest and digest responses.
    • Example: Stimulates digestion, increases salivation, and slows heart rate during meal times.

Summary

  • CNS: Brain and spinal cord.
  • PNS: Nerves throughout the body, with somatic (voluntary) and autonomic (involuntary) subdivisions.
  • ANS: Further divided into sympathetic (fight or flight) and parasympathetic (rest and digest) systems.