Lecture Notes: Divisions of the Nervous System

Introduction

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Nervous System Overview

• Divisions:
  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)

Central Nervous System (CNS)

• Comprises the brain and spinal cord.
• Functions:
  • Processes and stores information.
  • Coordinates signals in and out.

Peripheral Nervous System (PNS)

• Function: Transmits information between the CNS and the rest of the body.
• Divisions:
  • Sensory Division (Afferent)
  • Motor Division (Efferent)

Sensory Division (Afferent)

• Role: Senses and transmits signals to the CNS.
• Sensory Neurons: Carry signals such as sight, smell, touch, and pain to the CNS.
• Process: Signals are sent to CNS (spinal cord and brain) for processing and response.

Motor Division (Efferent)

• Role: Transmits signals from the CNS to target cells.
• Types of Responses:
  • Voluntary: Consciously controlled.
  • Involuntary: Not under conscious control.

Somatic Nervous System

• Function: Controls voluntary movements.
• Example: Signal transmission to skeletal muscles for movement.

Autonomic Nervous System

• Function: Controls involuntary responses.
• Further Divisions:
  • Sympathetic Division
  • Parasympathetic Division

Sympathetic Division

• Role: Active during exercise (fight-or-flight response).
• Effect: Increases heart rate and activity during exercise or stress.

Parasympathetic Division

• Role: Active during rest and digestion (rest-and-digest response).
• Effect: Decreases heart rate, active during eating and resting.

Conclusion

• Summary:

  • CNS consists of the brain and spinal cord.
  • PNS has sensory and motor divisions.
  • Motor division involves somatic (voluntary) and autonomic (involuntary) systems.
  • Autonomic system includes sympathetic (active) and parasympathetic (resting) divisions.

• Key Takeaway: Sympathetic and parasympathetic divisions have opposing effects on organs.