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BACKGROUND INFORMATION
Nicotine and it’s Effect on the Body and Brain
“The Effects of Extended Pre-Quit Varenicline Treatment on Smoking
Behavior and Short-Term Abstinence: A Randomized Clinical Trial”
BACKGROUND
About one in every five deaths each year is caused from cigarette smoke. Smoking is the largest cause of death
in the United States that can be prevented. Nicotine is a highly addictive substance found in the tobacco
used to make cigarettes. An addiction is a harmful habit that can be pleasurable but becomes compulsive
(uncontrollable habit) and interferes with a person’s life or health.
Cigarettes create dangerous health risks to the human body. For example, the chemicals in cigarettes can cause
cancer in different organs throughout the body. In the circulatory system cigarette smoke can narrow the blood
vessels and decrease the amount of blood flow. The small particles, particulates, are found in cigarette smoke
and end up in the respiratory system. Particulates cause coughing, irritation to the lungs, and asthma attacks.
They have even been linked to diseases such as emphysema and cancer.
Carbon monoxide, a chemical that forms when a cigarette burns, enters the body through the respiratory
system. Carbon monoxide is a poisonous gas that decreases the amount of oxygen absorbed by the body’s cells.
Red blood cells, RBC, carry oxygen, O2 , from the lungs to the cells. The oxygen that we breathe consists of two
atoms of oxygen that are held together by sharing four electrons (two from each atom). When two electrons
are shared between two atoms, they form a bond. Gas atoms that are bonded together form a molecule. In
this case, there are four electrons shared, so the oxygen molecule forms a double bond, represented by the
double lines:
Oxygen
Oxygen
When an RBC reaches the cell, it releases the O2 for the cell to use. The cell releases carbon dioxide, CO2,
which is a waste product from the cell. Carbon dioxide consists of one carbon atom bonded with two oxygen
atoms. There is a double bond between each oxygen atom and the carbon atom. Because the carbon atom is in
the middle, it is called the “central atom”:
Teacher Enrichment Initiatives/CAINE
2013© The University of Texas Health Science Center at San Antonio
STUDENT SECTION
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BACKGROUND INFORMATION
Nicotine and it’s Effect on the Body and Brain
“The Effects of Extended Pre-Quit Varenicline Treatment on Smoking
Behavior and Short-Term Abstinence: A Randomized Clinical Trial”
The RBC picks up the CO2 and carries it to the lungs where it is released by the RBC. The RBC can now pick up
more O2 and the cycle begins again.
When cigarette smoke is present in the lungs, instead of being able to pick up an O2 molecule, the RBC will pick
up a carbon monoxide, CO, molecule. The CO molecule consists of one carbon atom and one oxygen atom that
share six electrons. This forms a triple bond:
If the RBC picks up a CO molecule, it will release the CO when it reaches the cells. The CO is taken into the cell,
but, the cell needs O2 to survive. Without O2 , the cell will die.
BRAIN CHEMISTRY AND HOW VARENICLINE WORKS
There are millions of nerve cells in the body. Nerve cells are called neurons and they have a very different
shape than most other cells in the body. The cell body contains structures found in other body cells (such
as the nucleus and mitochondria). A nerve cell body has dendrites that reach out into the surrounding space
to receive chemical signals from surrounding nerve cells. This space is called the synapse. These chemical
signals are called neurotransmitters (nur-ro-TRANS-mit-ter). The dendrites have specialized receptors
sensitive to specific neurotransmitters. When a receptor is activated by a neurotransmitter, it sends a chemical
signal from the dendrite, through the cell body, and into an elongated section of the nerve called the axon.
When the chemical signal reaches the terminal ends of the axon, it releases neurotransmitters into the synapse
and the process repeats along the nerve pathway until the final destination is reached.
OUTPUT from other neurons
INPUT from other neurons
Sends Signal Down the Axon
Axon
Dendrites
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STUDENT SECTION
Synapse
Cell Body
Terminal Branches
Teacher Enrichment Initiatives/CAINE
2013© The University of Texas Health Science Center at San Antonio
Neurotransmitter
BACKGROUND INFORMATION
Nicotine and it’s Effect on the Body and Brain
“The Effects of Extended Pre-Quit Varenicline Treatment on Smoking
Behavior and Short-Term Abstinence: A Randomized Clinical Trial”
The neurotransmitters in the brain are responsible for how we react to internal and external stimuli. They
determine memory, movement, sleep, and learning. No stimulus or response can happen in the nervous system
without the neurotransmitters. The neurotransmitters can either cause an effect or feeling (excitatory) or
prevent an effect or feeling (inhibitory).
A neurotransmitter made in the body is acetylcholine (a-SEA-til-co-leen). It delivers signals from the
brain to muscles and also controls basic functions like heart beat and breathing. It also controls the flow of
information in the brain. Since acetylcholine is important for keeping the brain and nervous system working
properly, it is released in small amounts and is closely regulated by the body.
Nicotine enters the body through the lungs as cigarette smoke is inhaled. Once in the lungs, it travels
through the bloodstream and into the brain. The nicotine molecule has a shape very similar to acetylcholine
and actually fits into the receptor site for acetylcholine on neuron dendrites. Unlike acetylcholine, nicotine is
not regulated by the body. Nicotine activates neurons in many different regions of the brain all at once which
misleads many neurons into releasing unusually large amounts of another neurotransmitter—dopamine
(DOEpah-meen). The release of dopamine causes smokers to experience pleasant, happy feelings and a
sensation of increased energy. This leads to addiction by reinforcing the smoker’s desire to smoke again
and again.
REFERENCES
Psychology Today
http://www.psychologytoday.com/basics/addiction
Centers for Disease Control and Prevention
http://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/effects_cig_smoking/#children
National Institute of Drug Abuse
http://www.drugabuse.gov/drugs-abuse/tobacco-addiction-nicotine
Teacher Enrichment Initiatives/CAINE
2013© The University of Texas Health Science Center at San Antonio
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