Nervous System Organization

Anatomical Organization of the Nervous System

• Central Nervous System (CNS)

  • Comprises the brain and spinal cord.

• Peripheral Nervous System (PNS)

  • Consists of all nerves outside the CNS.
  • Supports communication between CNS and the rest of the body.

Functional Organization of the Nervous System

• Central Nervous System (CNS) remains the same, comprising the brain and spinal cord.

• Peripheral Nervous System (PNS) further divides into several functional categories:

  • Sensory Division

  • Responsible for sensing environmental stimuli (e.g., pain, temperature).

  • Delivers sensory information to the CNS.

  • Mnemonic: "A for Average and A for Approaching" symbolizes incoming signals to the CNS.

  • Efferent Division

  • Responsible for conveying information from the CNS to the periphery.

  • Mnemonic: "E for Exiting" symbolizes outgoing signals from the CNS.

  • Somatic Motor Division

    • Regulates voluntary skeletal muscle movements.

  • Autonomic Motor Division

    • Responsible for regulating automatic processes (e.g., heart rate, digestion).
    • Further subdivided into two categories:
    • Sympathetic Division
      • Becomes active during stress, emergencies, or high activity.
      • Prepares the body for "fight or flight" responses (e.g., increases heart rate and blood pressure).
    • Parasympathetic Division
      • Active during rest and relaxation ("rest and digest").

Summary

• The nervous system is divided into anatomical and functional components.
  • CNS: Brain and Spinal Cord.
  • PNS: Sensory Input and Efferent Divisions (Somatic and Autonomic).
• The autonomic division plays a crucial role in regulating involuntary bodily functions, adapting to internal and external stimuli based on the body's needs.