Chapter Three: The Biological Bases of Behavior

B. Organization of the Nervous System

Your nervous system is organized into the peripheral and central nervous systems.

1. Peripheral Nervous System
2. Central Nervous System

Contents

Peripheral Nervous System

The peripheral nervous system is made up of all those nerves that lie outside the brain and spinal cord.

• Introduction

  Organization of the nervous system (Figure3.8)
  
  What are nerves?
  
  Subdivision of peripheral nervous system

  • Somatic nervous system
  • Autonomic nervous system

  
  

• Somatic Nervous System

  The somatic nervous system lets you feel the world and move around in it.
  

  • Afferent nerve fibers
    - information goes inward.

  • Efferent nerve fibers
    - information goes outward.

  • Each body nerve contains axons of both types.

• Autonomic Nervous System

  The autonomic nervous system controls the automatic, involuntary functions that people don't normally think about.
  
  
  Fight or flight response to chapter 13 (Stress).
  
  Branches

  • Sympathetic division
    - activates the emergency response.

  • Parasympathetic division
    - calms the system down.

Central Nervous System

The central nervous system consists of the brain and spinal cord.

• Introduction

  • Meninges - sheaths which enclose the brain
  • Cerebro-spinal fluid (CSF) nourishes and cushions the brain.
  • The Blood-brain barrier
    guards the brain.

• The Spinal Cord

  The spinal cord connects the brain to the rest of the body.
  
  

  	3-D image of spinal cord: Click the "Label All" button to see the parts labeled.
  	An animated movie is available here also.

• The Brain

  Contains "billions and billions" of cells -- the topic of the next three sections:

  • Methods of investigating brain-behavior relationships.

  • Functions of the brain.

  • Right Brain/Left Brain.

  
  

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