Grant Clay
Period 3

AP Psychology Outline
Chapter 3: The Biological Bases of Behavior

Red - Definition
Blue - Important Points
Green - Important People & Contributions

Nervous System: The Basics
1. Neurons - Individual cells in the nervous system that receive,
integrate, and transmit information.
a. They are basic links that allow communication within the Nervous
b. Soma - Cell Body of the neuron that contains the nucleus and
much of cells normal organs.
c. Dendrite - Parts of a Neuron that receives information.
d. Axon - Long fiber that transmits information away to other
neurons, muscles, or glands.
e. Myelin Sheath - Insulating Material that encases some Axons.
i. It speeds up to transmission of information.
f. Terminal Button - Small knobs where neurotransmitters are
transmitted activating neighboring neurons.
g. Synapse - Junction where information is transmitted from one
neuron to another.
h. There is lots of variety among Neurons, so not all neurons
contain all these parts.
2. Glia - Cells in Nervous System that provides various support for
a. Glial cells supply nourishment to neurons, remove neurons waste
products, and provide insulation around many axons.

The Neural Impulse: Using Energy to Send Information
1. Neural Impulse - The signal that moves through the Neuron.
2. All the Study of the Neuron done on a Squids Neuron (Which is
much bigger than a Humans) By Hodgkin and Huxley.
1. Neuron At Rest
. The Neuron at rest is a small battery, from the uneven Ion
charges from the fluid around it of Sodium (Na) and
Potassium (K).
. Resting Potential - The Stable, Negative Charge when the
Cell is inactive.
2. The Action Potential
. Action Potential - A very brief shift in a Neuron's
electrical charge that travels along an axon.
. Absolute Refractory Period - Minimum length of time after
an action potential during which another action potential
cannot begin. Only about 1 or 2 Milliseconds.
. All-Or-None Law - Neural Impulses either Fire or don't
fire. There is no Half-Fire. A faster Rate of transmission
means a stronger Stimulus.
3. The Synapse
. Synaptic Cleft - The gap between the terminal button of one
neuron and the cell membrane of another neuron.
. The two Membranes of the different Neurons do not touch.
. Neurotransmitters - Chemicals that transmit information
from one Neuron to another.
. Synaptic Vesicles - The body that Neurotransmitters
are transmitted across the gap in.
. Pre-Synaptic Neuron - The Neuron that sends the
Signal across the Gap.
. Post-Synaptic Neuron - The Neuron that receives the
. Receptor Site - Where the Synaptic Vesicles bind
releasing the information into the new Neuron.

4. Receiving Signals: Postsynaptic Potentials
. Post-Synaptic Potential (PSP) - A voltage change at the
receptor site on a postsynaptic cell membrane.
. PSP's are not All-Or-Nothing Law; they are graded and
increase/decrease the probability of a neural impulse in
the receiving Cell.
. Excitatory PSP - Positive Voltage shift, Increases
likelihood that Postsynaptic Neuron will fire Action
. Inhibitory PSP - Negative Voltage shift, decreases
likelihood that Postsynaptic Neuron will fire Action
. The Voltage shift depends upon which Receptor Sites
are activated in the Postsynaptic Neuron.
. Reuptake - Process which Neurotransmitters are
sponged up from the synaptic cleft by the Presynaptic
. Thousands of Neurons are connected to Thousands of
. If there is enough Excitatory PSP's, electrical
voltage builds up to the threshold where an Action
Potential can be fired. However, many Inhibitory
PSP's will cancel the effects of the Excitatory

5. Neurotransmitters and Behavior
. Acetylcholine - Transmitter between Motor Neurons and
Voluntary Muscles.
. Agonist - Chemical that mimics the action of a
. Antagonist - Chemical that opposes the action of a
. The Agonist causes PSP's, while the Antagonist Blocks
. Monoamines - 3 Neurotransmitters: Dopamine, Norepinephrine,
and Serotonin.
. Dopamine - Used by Neurons that Control Voluntary
1. Degeneration of Dopamine leads to Parkinson's
. Serotonin - Plays a prominent role in sleep,
wakefulness, and eating Behavior.
. Abnormal levels of Monoamines lead to Psychological
. Depression = Low activation of Norepinephrine and
Serotonin Synapses.