Transcript ch.-18-Fighting-Diseases-1

Ch. 18
Fighting Disease
Section 1: Infectious Disease
Infectious Diseases
• A disease that is caused by the presence of a living
thing within the body.
• They are a result of pathogens getting into your body
and causing harm.
• Pathogens are organisms that cause disease.
• They make you sick by damaging individual cells. (ex.
Strep throat attacks your cells in your throat)
Joseph Lister
• British surgeon in the 1860s.
• Hypothesized that microorganisms caused
diseases.
• He began to wash his hands and clean his
instruments. As a result the risk of infection
decreased drastically.
Louis Pasteur
• A French Scientist in the 1860s
• Showed that certain organisms caused certain
diseases.
• He showed that by killing the microorganisms
could prevent the spread of that disease.
Robert Koch
• German physician in the 1870s and 1880s
• Demonstrated that specific pathogens caused
certain diseases.
Kinds of Pathogens
• Bacteria, Viruses, Protist, Fungi
• Bacteria- ear infections, strep throat, food
poisoning.
• Viruses- colds and flu
• Protist- Malaria, Amebic dysentery
• Fungi- athletes foot and ring worm
How Pathogens are spread
• Pathogens can spread through contact with
either an infected person, soil, food, or water,
a contaminated object or animal.
• Some can contaminate food or water.
(dysentery)
How are Pathogens Spread
• Some pathogens can survive outside of the body.
(cold and flu)
• You can be infected by touching contaminated
objects.
• You can also catch diseases from infected animals.
• If you are bitten by a Deer Tick that is carrying Lyme
Disease then you can catch that disease.
Questions
1. What is a Pathogen?
2. How do Pathogens cause infectious diseases?
3. How did Pasteur and Koch contribute to the
understanding of the causes of infectious
diseases?
4. What are 4 ways pathogens can infect
humans?
Ch. 18, Section 2
• The Body’s Defenses
Barriers that keep pathogens out
• Skin, Breathing passages, mouth and stomach
• Skin doesn’t let most pathogens in. A cut
however can allow pathogens to enter the
body.
• Pathogens can enter through nose and mouth
when you are breathing.
• Mucus and cilia trap and remove most
pathogens.
Inflammatory Response
• The body’s second line of defense. It responds
the same to all pathogens.
• Fluid and white blood cells leak from blood
vessels into nearby tissues.
• The white blood cells then fight the pathogens.
• A phagocyte is a white blood cell that engulfs
pathogens and destroys them by breaking them
down.
• What type of white blood cells are apart of the
inflammatory response?
The Immune System
• Immune response is the body’s third line of defense.
Triggers when a pathogen causes a fever.
• T-cell- identifies pathogens and distinguish one kind
of pathogen from another.
• Antigen- molecules that the immune system either
recognizes either as part of your body or as coming
from outside your body.
T-Cell
Immune System
• B-cell- produce proteins that help destroy
pathogens.
• These are called antibodies.
• Antibodies: proteins that help destroy
pathogens.
• Antibodies destroy pathogens by binding to
antigens on a pathogen.
AIDS
• AIDS- Acquired immunodeficiency syndrome is
caused by HIV (Human immunodeficiency virus)
• HIV attacks the immune system and destroys Tcells.
• Eventually the body is unable to fight off
diseases.
• There is no cure for AIDS, there are medicines
that allow people to live much longer than those
in the past.
Section 3, Preventing Infectious
Diseases
• Active Immunity- the body has produced
antibodies that fight a certain disease.
• Ex. You only catch the Chicken Pox Virus once.
• A person acquires active immunity when their
own immune system produces antibodies in
response to the presence of a pathogen.
Immune Response
• 1st way to gain active immunity
• Memory cells in your body recognize antigens
and then your body is able to fight off the
pathogen before you get sick.
Vaccination
• 2nd way to gain active immunity
• Harmless antigens are introduced to a persons body
to produce active immunity.
• Given by injections, mouth, or a nasal spray.
• This allows your body to produce memory cells.
• Vaccines are made from weakened or dead
pathogens.
• You usually do not get sick from vaccines.
When you do get sick
• Antibiotics are used to fight off bacterial
infections.
• It is a chemical that kills bacteria or slows their
growth without harming body cells.
• They do not kill viral diseases.
• When you are sick you should get plenty of
rest, drink fluids, and eat a well balanced
meal.
Passive Immunity
• Antibodies are given to a person, the person’s
immune system does not make them.
• So they are coming from an outside source.
• Rabies is a very uncommon disease that
people do not receive vaccinations for.
• If a person has rabies they have to inject the
antibodies into them to fight off the disease.
Section 4
Noninfectious Diseases
• Noninfectious Diseases have grown more
common in today’s world.
• These are diseases that are not caused by
pathogens.
• They cannot be transmitted from person to
person.
• Ex. Heart disease, cancer, allergies, diabetes
Allergies
• Disorder where the immune system is overly
sensitive to a foreign substance.
• Allergens are any substance that causes an allergy.
• Dust, pollen, food, and molds can cause allergies.
• you can inhale, touch, or eat them.
• A histamine is a response to an allergy. (sneezing)
• Drugs that interfere with symptoms are
antihistamines.
• Some allergic reactions can cause asthma.
Allergens
Diabetes
• Diabetes happens when the pancreas fails to
produce enough insulin or the body’s cells fail to
properly use insulin.
• As a result someone with diabetes has high levels of
glucose in the blood.
• Their cells however do not have enough glucose.
• Long terms effects can be blindness, kidney failure,
heart failure.
2 Types
• Type 1: pancreas produces little to no insulin.
• Must receive insulin injections.
• Develops in children and early adulthood.
• Type 2: pancreas doesn’t make enough insulin or the
body cells do not respond normally to insulin.
• Occurs in adulthood.
• Proper diet, weight control, and exercise can prevent
it.
Cancer
• Is a disease in which cells multiply uncontrollably
destroying healthy tissue in the process.
• How does it develop?
• As cells divide over and over they often from
abnormal tissue masses called tumors.
• Not all tumors are cancerous.
• Cancerous tumors invade and destroy healthy tissue
around them.
• It can eventually can get into your blood or lymph
vessels, which can carry the cancer all over your
body.
Cancer cell
Treatment and Prevention
• Treatment:
• Surgery, chemotherapy, radiation are used to
treat cancer.
• Prevention:
• Avoid carcinogens (smoking, chewing tobacco,
etc.) low fat diet (eat plenty of fruit and
vegetables, regular medical checkups.