Transcript Slide 1 - Garnet Valley School District

Understanding Diseases
Chapter 8 Lesson 1
Focus Question
Name different diseases.
Diseases you can catch
Diseases you cannot
catch
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Understanding Diseases
A communicable Disease is an illness
caused by pathogens that can be passed
from one person to another person, animal
or object.
A germ is something that causes disease.
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A more official term for germ is PATHOGEN!
They are disease causing agents which could be
single or multi-cellular.
Causes and Spread of Disease
Pathogens come in all different shapes
and sizes:
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Such as: bacteria, protozoa, fungi, rickettsia,
and viruses.
Not all Bacteria and Fungi are pathogens!
Some bacteria are beneficial and used in the
digestion process.
Some Fungi are used as food (mushrooms)!
Type of
Pathogen
Description
Diseases
Bacteria
Single celled organism that live
nearly everywhere! They rapidly
reproduce!
Strep throat, lyme
disease, urinary tract
infections
Viruses
Smallest and simplest pathogens.
They reproduce inside healthy cells.
Colds, chicken pox,
small pox, measles,
herpes
Protozoa
Single celled organisms that capture
other life forms for food. Live within
the body as parasites.
Malaria, dysentery
Fungi
Single celled or multi cellular
organisms that feed on organic
material. Yeasts and molds cause
diseases.
Athletes foot, ring worm,
nail fungal infections.
Rickettsia
Pathogens similar to bacteria but
multiply like viruses.
Typhus, Rocky Mountain
Spotted fever.
How are Pathogen’s Spread?
Direct Contact

Kissing, touching, sharing glasses or utensils,
sexual activity, needle sharing.
Animal bites or scratches
Indirect contact
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Doorknobs, table tops, faucet handles
Insect Stings or bites
Contaminated food or water
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Food borne illnesses, etc
Wash your Hands!!!
Soap or alcohol-based hand rub kills the flu virus. When water is
not available, alcohol-based hand rubs may be used. It’s
especially
important to clean your hands:
• After wiping or blowing your nose or coughing or sneezing;
• After using the bathroom;
• After being in contact with or being near someone who is ill;
• After touching handrails, doorknobs, telephones or other
things handled by many people;
• Before and after eating or drinking;
• Before handling food, especially ready-to-eat foods like
salads
and sandwiches; and
• After handling garbage or trash
The Immune System
Made of cells, tissues, and organs that fight off
pathogens.
First line of defense:
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Skin
Mucous Membranes
Tears
Saliva
Sweat
Stomach Acid
Once the pathogen’s get in…
The Immune System
The Immune System’s Specific
Response
This is the body’s
third line of defense
Lymph contains
lymphocytes
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Lymph plays an
important part
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It bathes cells and
cleans them of foreign
organisms.
Lymph nodes filter the
lymph.
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B-Cells- make T cells
T-Cells- destroy
infected cells
Killer Cells- kill
pathogens
The Immune System’s Specific
Response
Antigens- substances that cause an immune reaction in
the body.
Once B-Cells find antigens, they begin making
antibodies.

Antibody- a protein in the blood that destroys a specific antigen.
Memory cells remember the specific antigen and they
speed the production of more antibodies.
T-cells and Killer Cells destroy the antigens as well.
Specific Parts of the Immune
System
Lymph Nodes
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Lymph carries captured antigens to lymph nodes
where it is filtered out.
Thymus
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Small gland on the upper chest that produces T-Cells
Spleen
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Filters dangerous substances from the blood. Carries
antigens to the spleen which prompts B-Cells to
produce antibodies.
Bone Marrow
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Bone Marrow produces lymphocytes
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Immune System Quiz
Caring for your Immune System
Get regular physical examinations
Visit a physician when you feel ill.
Follow directions on your medication.
Reduce Stress
Exercise Regularly.
Get 8 hours of sleep each night
Plan healthy meals
Avoid drugs and alcohol.