FIGHTING DISEASE
Mr. Gagnon
Fighting Disease:
6.1 Infectious Disease:
Key Terms:
- Pathogens
- Infectious Disease
- Toxin
Key Concepts:
- What kinds of organisms cause
disease?
- Where do pathogens come
from?
SURGICAL HISTORY
Surgery Pre-twentieth Century
 Surgery before the 1900’s was
very risky.
 Many patients died after
surgery.
 Joseph Lister hypothesized
that microorganisms infected
his patients.
 Lister used carbolic acid to
sterilize his tools and on
bandages post surgery.
DISEASE AND PATHOGENS
Illness
 Food poisoning and ear
infections are caused by living
things too small to see.
 Pathogens- are organisms
that cause disease.
 Infectious disease- is a
disease that can be passed on
from one organism to another.
Key Advances in Understanding
 Lister was influenced by Louis
Pasteur who showed that
killing microorganisms can
prevent the spread of disease.
 Robert Koch in 1870’s and
80’s demonstrated that
infectious diseases are caused
by specific microorganisms.
 Ecoli, is an example.
KINDS OF PATHOGENS
Bacteria
 Bacteria are one celled
microorganisms.
 Ear infections, food poisoning,
tuberculosis.
 Pathogens damage cells
directly and invade cells, or
create a toxin, a poison that
damages cells.
Viruses
 Viruses cannot reproduce on
their own.
 They invade cells, reproduce,
and then spread through the
body.
 Influenza (the flu), Chicken
Pox, and AIDS.
HOW DO SCIENTISTS IDENTIFY THE
PATHOGEN THAT CAUSES A SPECIFIC
DISEASE?
FUNGI AND PROTISTS
 Fungi (molds, yeasts, mushrooms, other organisms) cause some
infectious diseases.
 Athlete’s foot is an example of fungal infection.
 Malaria is caused by protists.
HOW CAN YOU BECOME INFECTED?
 Person to Person- through contact with another person.
 Contaminated Objects- some pathogens survive on surfaces (ie.
Desks).
 Animal Bites- rabies (animals like raccoons) and Lyme disease
(deer ticks).
 Natural Environment- tetanus (soil and water) and botulism
(bacteria in food).
PATHOGEN COMIC
PATHOGEN COMIC
PATHOGEN COMIC
Fighting Disease:
6..2 The Body’s Defenses:
Key Terms:
- Inflammatory Response
- Phagocyte
- Immune Response
- Lymphocyte
- T Cell
- Antigen
- B Cell
- Antibody
- AIDS
Key Concepts:
- What is the body’s first line of defense?
- What happens during an inflammatory
response?
- How does the immune system respond to
pathogens?
THE BODY’S BARRIERS
(1ST LINE OF DEFENSE)
The Skin
 Oils and sweat battle bacteria
on the surface.
 Pathogens on dead skin cells
fall to the ground.
 Pathogens may enter at open
cuts, but scabs form over
those surfaces.
The Breathing Passages
 The nose, pharynx, trachea,
and bronchi have mucus and
cilia that catch the pathogens.
 Coughing and sneezing helps
expel these pathogens.
THE BODY’S BARRIERS
(1ST LINE OF DEFENSE)
Mouth and Stomach
 Saliva contains enzymes that
help break down pathogens.
 The stomach produces acid to
fight pathogens.
OTHER DEFENSES
 Inflammation- Fluid and
certain types of white blood
cells leak from blood vessels
into nearby tissue. The WBC
then fight the pathogen.
 Phagocytes are involved in
inflammation. They are the
WBC’s that engulf pathogens
and destroy them by breaking
them down.
DURING THE INFLAMMATION RESPONSE
 Blood vessels widen (dilate).
 Fluid leaks out of the vessels causing
redness and swelling.
 May cause a fever due to chemical
release.
THE IMMUNE SYSTEM
 The immune response is the
body’s 3rd line of defense that is
controlled by the immune
system.
 The immune system uses
lymphocytes, which are WBC’s
that identify and destroy
pathogens.
 T-Cell Lymphocytes are WBC’s
that distinguish one kind of
pathogen from another.
 Antigens are marker molecules
on the exterior of cells that a tcell recognizes as either part of
the body or not.
 B-Cell Lymphocytes are WBC’s
that produce chemicals that help
destroy pathogens.
 Antibodies are the chemicals
produced by the b-cell
lymphocytes sent to destroy the
pathogen.
HIV/AIDS
 HIV/AIDS is the acquired immunodeficiency that attacks
the immune system.
 This virus attaches and reproduces within a t-cell
lymphocyte.
 This makes it difficult for the lymphocytes to recognize the
pathogens.
 People who die from AIDS often die from the common cold
or flu because the body cannot recognize and fight the
pathogens.
Fighting Disease:
6.3 Preventing Infectious
Disease:
Key Terms:
- Immunity
- Active Immunity
- Vaccination
- Vaccine
- Passive Immunity
- Antibiotic
Key Concepts:
- What is active immunity?
- What is passive immunity?
ACTIVE IMMUNITY
 Once you have the chicken pox virus, do you get it a second time? Why
or why not?
 Active Immunity occurs when a person’s own immune system
produces antibodies in response to the presence of a pathogen.
 Active immunity is produced by the cells of a person’s immune system.
 The person’s T-Cells and B-Cells “remember” previous viruses that they
had to destroy.
ACTIVE IMMUNITY
 If a person does not contract a disease, he/she could still become
immune.
 Vaccination is the process by which harmless antigens are deliberately
introduced into a person’s body to produce active immunity.
 The vaccine is the substance shot into the vaccinated person that
usually consists of pathogens that have been weakened or killed but still
triggers the immune system into action.
PASSIVE IMMUNITY
 Passive Immunity is when someone is given a shot of antibodies after
he/she has contracted antigens (ie. Rabies).
 Passive immunity occurs when the antibodies that fight the pathogen
come from another source rather than from the person’s body.
STAYING HEALTHY
 Don’t share items that might be contaminated (straws, toothbrushes, or
silverware).
 Keep clean.
 Cover your mouth when coughing, preferably your elbow.
 Get 8hr of sleep each night.
 Eat a well balanced diet.
 Get regular exercise.
RECOVERING WHILE SICK
 Get plenty of rest.
 Eat well balanced meals.
 Drink fluids.
 Take antibiotics, a chemical that kills bacteria or slows their growth, if
instructed by a doctor.
 There are not medicines for viral illnesses, like the common cold. Get
plenty of rest.
Fighting Disease:
6.4 Noninfectious Disease:
Key Terms:
- Noninfectious Disease
- Allergy
- Allergen
- Histamine
- Asthma
- Insulin
- Diabetes
- Cancer
- Tumors
- Carcinogens
Key Concepts:
- What is an allergy?
- How does diabetes affect the body?
WHAT IS A NONINFECTIOUS DISEASE?
 A Noninfectious Disease is a disease that is not spread from person to
person.
 Examples:
 Allergies
 Diabetes
 Cancer
WHAT ARE ALLERGIES?
 An allergy is a disorder in which the immune system is overly sensitive to a foreign substance
(something not normally found in the body).
 Allergies are caused by allergens, which are any substances that cause an allergy (ie: pollen, dust,
molds, some foods, animals, and medicines).
 Allergens enter the system through inhalation, ingestion, or touch.
 Lymphocytes recognize the allergen and produce antibodies which signals the cells to produce
histamine.
 Histamine is a chemical responsible for the symptoms of an allergy (sneezing, watery eyes).
 Asthma, a disorder in which the respiratory passages narrow significantly, may develop from
allergens that are inhaled.
WHAT IS DIABETES?
 Diabetes is the condition in which either the pancreas fails to produce
enough insulin or the cell’s body can’t use it properly.
 As a result, a person with diabetes has high levels of glucose in the
blood (high blood sugar) and excretes glucose in their urine. The
person’s cells do not have enough glucose.
 Insulin is a chemical made in the pancreas to help take glucose (sugar)
from the blood and convert it into energy.
 Symptoms:
 Loss of weight, feel weak, hungry all the time, can result in death if not treated right.
WHAT ARE THE 2 FORMS OF DIABETES?
 Type 1- is the most serious form in which the pancreas produces little
or no insulin. This is childhood or early adulthood diabetes. These
patients must take insulin shots.
 Type 2- usually develops during adulthood, and the pancreas doesn’t
produce enough insulin or the body’s cells don’t use it properly. These
patients might not need to take insulin and can control it through diet
and exercise.
CANCER
 Cancer is a disease in which cells multiply uncontrollably, over and over,
destroying healthy tissue in the process.
 The division of cells over and over again forms abnormal tissue mass
called a tumor.
 Benign tumors do not spread throughout the body, while malignant
tumors spread uncontrollably.
CAUSES OF CANCER
 Heredity (susceptibility of getting cancer).
 Carcinogens are substances or factors found in the environment that
cause cancer (ie: UV rays, tar from cigarettes, etc.).
 Cancer Prevention
 Avoid all forms of tobacco
 Reduce exposure to sunlight
 Low fat diet w/ plenty of fruits and veggies
 Regular medical checkups for early detection