Chapter 4: The Nervous System

Components of the Nervous System

Homeostasis

Humans must maintain their environment within certain limits

Temperature

Acidity

Water content

Sodium content

Glucose concentrations

Psychoactive drugs impact homeostasis

The Nervous SystemsThe Nervous Systems

Somatic nervous system (SNS) Sensory information Voluntary actions

Autonomic nervous system (ANS) Sympathetic branch Parasympathetic branch

Central nervous system (CNS) Brain Spinal cord

The Brain: Major StructuresThe Brain: Major Structures

Cerebral cortex**

Cerebellum

Limbic system**

Brain stem**

Cerebral Cortex

“Gray Matter” Maintain cognitive functioning Divided into lobes:

Parietal Frontal Temporal Occipital

Limbic System

Emotional brain Drives Pleasure Formation of memories

Nucleus Accumbens Central part of limbic system “Reward Pathway”

Brain Stem

Extension of spinal cord Small but “mighty” All information from body to

major parts of brain goes through brain stem

Chemical Theories of BehaviorChemical Theories of Behavior

Variations in behavior explained through changes in brain chemistry Historical and cultural perspectives Monoamine theory of mood Issue of experimental support

Brain imaging techniques Types Reactions