Harmful Chemicals:
Your body uses many different kinds of
chemicals; however some chemicals can
harm your health.
Cancer
 Cancer is a group of diseases caused by
abnormal cell growth and reproduction.
 Different kinds of cancer can affect
specific organs.
 All forms of cancer involve the
uncontrolled growth of body cells.
 Organisms grow as a result of cell
division, which is usually controlled.
 Cancer affects cell division and causes
uncontrolled cell division that forms
abnormal cells or unusually large
numbers of cells.

 Cells joining together in a large mass are
known as a tumor.
 Some cancers are caused by exposure to
certain chemicals.
 A chemical that causes cancer is called a
carcinogen.
 For example, lung cancer is often caused
by carcinogens in tobacco products.
Birth Defects
 Some chemicals can cause birth defects.
 Smoking during pregnancy increases the
baby’s chances of being premature,
having a low birth weight, being stillborn,
and having birth defects.
 A woman who drinks alcohol during
pregnancy may have a baby with fetal
alcohol syndrome (FAS).
 This may result in brain damage creating
learning disabilities and/or behavioral
problems.
 Not drinking alcohol while pregnant
eliminates the risk of FAS.

*A birth defect affects about 1 in every 33
babies born in the U.S. Some are minor and
nearly noticeable. Others can be serious or
even fatal.
Heart Disease
 Heart disease is the leading cause of
deaths in the U.S.
 Heart disease occurs when the arteries
that supply blood to the heart are
narrowed or blocked.
 Nicotine in tobacco is one product that
causes arteries to narrow.
 Cholesterol, a fatty acid, is a chemical
that can cause heart disease.
 It can build up and block the arteries
restricting the blood’s flow and
resulting in a heart attack.
Kidney Disease
 The kidneys are the main organs of the
urinary system that filter waste products
from the blood.
 Some chemicals can harm the kidneys and
cause kidney disease.
 Exposure to chemicals can create waste
build up, known as kidney stones.
 Kidney stones block the ureters, which
connect each kidney to the bladder,
blocking the flow of urine.
Asthma
 Harmful chemicals can also cause asthma,
which causes a person to breath with
difficulty.
 The passages (bronchi) that lead from the
throat to the lungs swell and become
inflamed.
 Inhaling harmful chemicals, such as
cleaning products, can cause an asthma
attack.
Review Questions:
1. Describe cancer and the general term for
a cancer-causing chemical.
- Cancer is caused by abnormal cell growth
and division. A carcinogen is a chemical
that causes cancer.
2. List two things a pregnant mother could
do to prevent her unborn baby from
having birth defects.
- Don’t smoke or drink alcohol.
3. List two things a person could do to
prevent heart disease.
- Don’t smoke, eat a low cholesterol (low
fat) diet.
4. Describe what an excessive exposure to
chemicals can do to the urinary system.
- Create a build up in wastes resulting in
kidney stones which block the flow of
urine.
5. What is asthma?
- Air passages swell and become inflamed,
making it difficult to breath.