Chapter Four: Neurons, Hormones, and the Brain

The Nervous System: A Basic Blueprint

INTRODUCTION

The function of the nervous system is to gather and process information, produce response to stimuli, and coordinate the workings of different cells.

WHAT'S AHEAD

• Why do you automatically pull your hand away from something hot, "without thinking"?
• Is it possible to consciously control your heartbeat or blood pressure?
• In an emergency, which part of your nervous system whirls into action?

KEY CONCEPTS

The Central Nervous System
The Peripheral Nervous System

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The Central Nervous System (p 114)

INTRODUCTION

Consisting of the brain and spinal cord, the CNS receives, processes, and stores incoming sensory information and sends outgoing messages.

KEY CONCEPTS EXPLAINED

Brain to detailed description.

Spinal cord

Acts as a bridge between the brain and the body below the neck.

spinal reflexes - produces behavior before information goes to the brain

• e.g. pulling your hand away from a very hot pot before you realize it is that hot. ((Don't try this at home as a psychological experiment!))
  
  
• spinal reflexes can be influenced by thoughts or emotions via pathways that run up and down the nervous system.

  e.g. Erotic thought --> spinal reflex of an erection .....Anxiety........--> loss of erection.

GLOSSARY

	central nervous system (CNS)
	spinal cord

LINKS About the CNS spinal cord

• www link: Anatomy of the Spinal Cord.
• www.link: Spinal Cord Injuries Resource Center.
• wwwlink: Spinal Cord Injuries Link Page AltaVista.
• wwwlink: Another Spinal Cord Injuries Link Page.

The Peripheral Nervous System [p.115]

INTRODUCTION

Consisting of all portions of the brain outside the brain and spinal cord, the PNS handles the input and output of the CNS.

KEY CONCEPTS EXPLAINED

Sensory nerves carry messages to the CNS spinal cord, motor nerves carry orders from the CNS to muscles, glands, and organs. Somatic nervous system (skeletal nervous system) nerves to and from the skeletal muscles that produce voluntary action. Autonomic nervous system automatically regulates the functioning of internal organs.

• Sympathetic nervous system automatically mobilizes the body for action. Important in stress reactions. (future fast forward to chapter 12)
  
  
• Parasympathetic nervous system turns down the sympathetic nervous system to return to normal and conserve energy.
  
  
• Biofeedback - a technique to control autonomic nervous system functions by providing biological feedback about the bodily process to the individual via a signal like a tone. The individual concentrates on raising or lowering the tone. This often produces the desired change in bodily functioning (e.g. lower blood pressure). (future fast forward to chapter 12)

GLOSSARY

	peripheral nervous system
	somatic nervous system
	autonomic nervous system
	sympathetic nervous system
	parasympathetic nervous system

LINKS about Peripheral Nervous System

• www link: More detailed figure of the Autonomic Nervous System.
• www link: Review Paper on Biofeedback.
• www.link: Example of how Biofeedback is conducted.
• wwwlink: Association for Applied Psychophysiology and Biofeedback.

Next Topic - Communication in the Nervous System..................... Chapter Contents