Download Module 36 Chapter 110 Essentials of Understanding Psychology

Module 5
Neurons: The Basic Elements of Behavior
Chapter 2
Essentials of Understanding Psychology- Sixth Edition
PSY110 Psychology
© Richard Goldman
October 4, 2006
Structure of the Neuron





Cell Body (soma)
Axon – single, long, sending arm
Dendrite – many, short, receiving arm
Myelin sheath – insulating coverings of axon
Terminal Buttons – bulge at end of axon
containing neurotransmitters
Neuron
Myelin Sheath
Body
(Soma)
Axon
Nucleus
Dendrites
Terminal Buttons
How Neurons Fire



Stimuli from dendrites produce action
potential
Action potential (electrical nerve impulse) Positive to negative reversal that prorogates
down axon
Action potential speed – 2mph-225mph
(thicker sheathed neuron transmit faster)
Neuron to Neuron







Synapse – gap between terminal button on axon and the
dendrite (or body) of another neuron
Nerve impulse triggers the release of neurotransmitter
chemicals into the synapse
Neurotransmitters (> 100 different chemicals) tend to
behave as either excitatory or inhibitory (their effect varies
at different sites)
Dendrites have specialize receiving sites for both
excitatory and inhibitory neurotransmitters
Enough excitatory neurotransmitters will trigger an
action potential in the dendrite
Inhibitory neurotransmitters mediate the potential of
triggering the dendrite
Reuptake: Synaptic neurotransmitters are either
neutralized by enzymes or reabsorbed into the axon
Major Neurotransmitters





Acetylcholine (ACh) (Excitatory) – Muscle &
Cognitive
Glutamate (Excitatory) – Memory
Gamma-amino butyric acid (GABA) (Inhibitory) –
Eating, Aggression, & Sleeping
Dopamine (DA) (Inhibitory or Excitatory) – Muscle
& Mental Disorders
Serotonin (Inhibitory) – Sleeping, eating, mood,
pain, depression
Endorphins (Mostly Inhibitory) – Pain
suppression, pleasure, appetite