Nervous System Organization Notes

Anatomical Organization of the Nervous System

• Central Nervous System (CNS)

• Comprises the brain and spinal cord.

• Responsible for processing and transmitting information.

• Peripheral Nervous System (PNS)

• Includes all nerves outside the CNS.

• Connects the CNS to the rest of the body.

Functional Organization of the Nervous System

Central Nervous System

• Functions similarly to its anatomical classification.
• Main components: brain and spinal cord.

Peripheral Nervous System Divisions

• Sensory Division

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

• Transmits sensory information to the CNS.

• Mnemonic: A for Average and A for Approaching signifies signals approaching the CNS.

• Efferent Divisions

• Information that exits the CNS and travels to the periphery.

• Mnemonic: E for Efferent and E for Exiting signifies signals exiting the CNS.

• Types of Efferent Divisions:

• Somatic Motor Division

  • Regulates voluntary movements of skeletal muscles.
  • Controls conscious motor activities.

• Autonomic Motor Division

  • Regulates involuntary processes (e.g., heart rate, digestion).
  • Controls automatic functions within visceral body cavities.
  • Has two further subdivisions:
  • Sympathetic Division
    • Activated during stress or emergency.
    • Increases heart rate and blood pressure, preparing the body for action (fight or flight response).
  • Parasympathetic Division
    • Activated during rest and relaxation.
    • Helps conserve energy and maintain functions during restful states.

Summary

• The nervous system is organized into CNS and PNS.
• PNS has sensory and efferent divisions with sub-divisions controlling various body functions, emphasizing the complexity of the nervous system's functional architecture.
• Understanding how these divisions work aids in comprehending the body's response to internal and external stimuli.