UNIT 1 – NEUROBIOLOGY
Nervous System
INTRODUCTION…
KEY TERMS
Abuse
 Addiction
 Neurobiology
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IS ADDICTION A DISEASE?
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Those who chronically use drugs do so because
they choose to. They lack the will power to stop.
= Psychosocial model of drug addiction
 Discriminates addicts
 Fail to provide them with medical care/treatment
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Addiction is a disease of the brain.
= Disease model of drug addiction
 Give addicts an excuse
 If you are fated to be an addict, lose will to try and
stop
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WHAT DO YOU THINK??
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Is addiction to alcohol or drugs a disease?

Write a few sentences on your position…
ADDICTION POPULARIZED

There is no lack of media
that portrays people with
addictions…good and bad…
DO WE WANT TO BE LIKE THEM?
Or are we well informed to make
good decisions?
 Is there some of both?
 Think of a song, commercial,
movie, or TV show that portrays
“abuse.”


How would you define “abuse” when
discussing drugs or alcohol?
WHY DO DRUGS AFFECT OUR MINDS?
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It really should come as no surprise that humans
experiment with drugs. We experiment with all sorts of
things that influence how we feel. From roller coasters to
television, we seek out activities that influence our
minds.
It might also come as no surprise that we have found
substances we can consume that influence our minds.
Imagine how early peoples must have experimented with
newly discovered plants and thereby found them to be either
nutritious or medicinal.
Similarly, some were found to have strange effects on our
mood.
Why? Why does nicotine effect how we feel?

The direct answer is that nicotine (and other mood-altering drugs)
has the ability to influence the chemistry of our brains. The
molecules within the plant can bind to molecules in our brains and
in so doing alter the function of the cells within.
REVIEW QUESTIONS:
1.
2.
3.
4.
What are mood altering drugs and why do they
affect us?
What is drug abuse?
What is drug addiction?
How are attitudes about drugs changing – and
how does that impact drug education?
NERVOUS SYSTEM
ORGANIZATION
KEY TERMS:
Central nervous system
 Peripheral nervous system
 Autonomic nervous system
 Sympathetic nervous system
 Parasympathetic nervous system

CENTRAL NERVOUS SYSTEM
The central nervous system is divided into two
parts: the brain and the spinal cord.
 The average adult human brain weighs 1.3 to 1.4
kg (approximately 3 pounds). The brain contains
about 100 billion nerve cells (neurons) and
trillions of “support cells” called glia.
 The spinal cord is about 43 cm long in adult
women and 45 cm long in adult men and weighs
about 35-40 grams.
 The vertebral column, the collection of bones
(back bone) that house the spinal cord is about 70
cm long. Therefore, the spinal cord is much
shorter than the vertebral column.

PERIPHERAL NERVOUS SYSTEM

The peripheral nervous system is divided into 2
major parts:
The autonomic nervous system
 The somatic nervous system

AUTONOMIC NERVOUS SYSTEM
Controls smooth muscle of the internal organs and
glands = “automatic functions”
 Divided into 2 parts:

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Sympathetic nervous system

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Involved in helping prepare the body for action – ex. Increasing
heart rate
Parasympathetic nervous system

Activate more calming functions – ex. Helps stimulate secretion of
saliva or enzymes for digestion
FIGHT OR FLIGHT VS. REST AND DIGEST

Sympathetic NS = Fight or Flight


Parasympathetic NS = Rest and Digest

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At times when we are under stress or having to
prepare major muscles to keep us alive
Regulate our body during times of calm
Though at certain times one may dominate over
the other, they never get turned “off”
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THESE SYSTEMS MUST BALANCE EACH OTHER
QUICK CHECK…

If a drug activates the sympathetic nervous
system, what symptoms do you expect that drug
to give the user?
Agitation, indigestion, and insomnia
B. Clammy hands, depression, and sleeping too much
C. Pin-point pupils (pupils constrict), weakness of
muscles, and indigestion
D. Muscles energized, depression, and slowed
breathing rate
A.
SOMATIC NERVOUS SYSTEM
(MOTOR SYSTEM = BODY MOVEMENT)
Peripheral nerve fibers send sensory information
to the central nervous system AND motor nerve
fibers that project to skeletal muscle
 Cells in the brain or spinal cord project messages
directly to skeletal muscle
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SOMATIC NS TEST…
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To examine your somatic nervous system, borrow a
friend.
Have that friend hold a dollar bill (or piece of paper)
in front of you with your fingers and thumb poised
right by the photograph of George Washington.
The idea is that when you see your friend release the
dollar bill, you will try to catch it between your
fingers and thumb. Are you able to do it?
The time it takes for you to clasp your finger and
thumb together is the time it takes your eyes to tell
your brain that the bill has been released, followed by
the time it takes your brain to instruct the fingers to
grasp.
Your somatic nervous system is very fast, but is it fast
enough????
QUICK CHECK…

Imagine the dollar bill experiment you just
considered. Instead of using your eyes, you close
them. How would your catching speed change if
you learned that the bill was being dropped by
having a friend kick your shoe?
A.
B.
C.
It would be faster.
It would be slower.
It would be the same.
QUESTIONS TO ANSWER…
What does the nervous system do (what is unique
about this system)?
 What are the parts of the CNS?
 What are the parts of the PNS (peripheral)?
 How are these different from the CNS?
 How is the ANS divided?
 What is the function of each of these parts?
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