Biology The Nervous System

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Pair-share

Do you think that chemicals and hormones in our bodies determine our behavior? (Discuss with your table partner).

Nervous SystemQ: Why do psychologists study the brain and the

nervous system? !

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.

!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.”

Nervous System

You have about 1 trillion nerve

cells in your body, and 100 chemicals that

transfer messages

between those nerves.

!(Those chemicals

are called neurotransmitters).

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)

NeurotransmittersNeurotransmitter 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

NeurotransmittersAn 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.

NeurotransmittersAn 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.

NeurotransmittersToday 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

NeurotransmittersEndorphins 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.

NeurotransmittersAcetylcholine 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.