1. © Richard Goldman October 4, 2006
Module 5 Neurons: The Basic Elements of Behavior Chapter 2 Essentials of Understanding Psychology- Sixth Edition PSY110 Psychology
© Richard Goldman
October 4, 2006

2. 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

3. Neuron Myelin Sheath Body (Soma) Axon Nucleus Dendrites
Terminal Buttons

4. 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)

5. 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

6. 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