Biology: Nervous System 1

1. Biology
The Nervous System
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2. Pair-share
Do you think that chemicals and hormones in
our bodies determine our behavior?
(Discuss with your table partner).

3. Nervous System
Q: Why do psychologists study the brain and the
nervous system?
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A: Some biological functions underly human behavior,
and in order to form a fuller understanding of ourselves,
it’s important to recognize what aspects of our behavior we
can attribute to our own bodies.
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Psychologists who examine behavioral problems based on the
ways in which our bodies affect our behavior are using the
“biological” or “neuroscience” approach. Psychologists who
specialize in studying the effects of biological functions on
behavior are called “behavioral neuroscientists.”

4. Nervous System
You have about
1 trillion nerve
cells in your
body, and 100
chemicals that
transfer
messages
between those
nerves.
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(Those chemicals
are called
neurotransmitters).

5. Nerve Ending (outgoing)
Nervous System
Neurotransmitters stimulate the nerve endings, or
transmit electrical impulses from the brain to the body.
Nerve Ending (incoming)
Neurotransmitters
(Axon)
(Dendrite)

6. Neurotransmitters
Neurotransmitter Name Function
Acetylchloline (ACh) Muscle movement, thinking/comprehending
Glutamate Memory
Gamma-amino butyric
acid (GABA)
Eating, sleeping, aggression
Dopamine (DA)
Movement control, attention,
pleasure and reward
Serotonin
Eating, sleeping, mood, pain, depression,
coping with stress
Endorphins
Pain suppression, pleasurable feelings,
appetite

7. Neurotransmitters
An excess or lack of certain neurotransmitters
can impact our behavior.
For example,
Parkinson’s Disease
causes the brain cells
that produce
dopamine to die.The
lack of dopamine in
the body leads to
shaking, irregular
movements, and loss
of motion control.

8. Neurotransmitters
An excess or lack of certain neurotransmitters
can impact our behavior.
Dopamine is also
associated with reward.
When we do things like
eating, exercise, and
“romancing,” dopamine
is released in our
brains. Certain drugs
like cocaine cause an
overproduction of
dopamine, mimicking
the reward sensation.
Studies show that unusually high amounts
of dopamine in our bodies is related to
schizophrenia.

9. Neurotransmitters
Today in modern medicine, glutamate-based drugs
are being tested to see if they help relieve symptoms
of clinical depression.
Symptoms of depression:
Loss of interest
Loss of appetite
Loss of energy
Feelings of loneliness
Feelings of worthlessness
Anger or irritability
Concentration problems
Reckless behavior

10. Neurotransmitters
Endorphins block pain in your body, and are also
responsible for some feelings of pleasure or happiness. A
lack of endorphins may be responsible for certain forms
of mental illness such as obsessive-compulsive disorder.
Some people who engage in
self-hurting behaviors may
do so in part to feel the
feelings of euphoria and
emotional isolation that can
be prompted by controlled
amounts of self-inflicted pain,
and subsequent release of
endorphins.

11. Neurotransmitters
Acetylcholine deficiency is an
abnormally low level of
acetylcholine.This
neurotransmitter is involved in
the control of muscle movement,
learning, and memory formation.
A lack of it causes uncontrolled
muscle movements and difficulty
forming and retrieving memories.
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Serotonin is a
neurotransmitter greatly
involved in your mood. If you’re
feeling pessimistic, sad,
distrustful, unconfident, or have
panic attacks, you may have a
serotonin deficiency.