1. Immune System The Germ Theory of Disease
In the mid-nineteenth century, Louis Pasteur and Robert Koch concluded that infectious diseases were caused by germs.

2. Immune System
Function- to recognize, attack, destroy, and “remember” each type of pathogen that enters the body.

3. A disease is any change, other than an injury, that disrupts the normal functions of the body.
Disease-causing agents are called pathogens.

4. Pathogens are destroyed by the body’s immune system.

5. The body’s immune system attacks and “remembers” each pathogen that enters the body.

6. Agents of Disease
Diseases are caused by Pathogens
they include:
viruses
bacteria
protists
worms
fungi

7. Diseases Are Spread by coughing sneezing physical contact
contaminated water or food
infected animals

8. Transmission of Disease
Direct Contact – touching an infected person
Examples – colds, STDs
Indirect Contact – touch infected surfaces or breath in pathogens from the air.
Sneeze, infected surfaces
Ingestion – drinking contaminated water or eating contaminated food
Amoebic dysentery, Salmonella, Botulism (canned food)
Vectors- organism that carries diseases and bites you.
Bubonic plague – spread fleas ,Malaria – mosquitoes, Lime’s disease– ticks, Rabies – dogs or squirrels

9. 1st Line of Defense - Nonspecific
First Line of Defense 
JOB- keeps pathogens out of the body.
Skin- Few pathogens can penetrate the layers of dead cells at the skin’s surface.
Most Important
Mucus and sweat – breaks down bacteria walls
Cilia in the nose and throat push pathogens away from the lungs.
Tears- flush out pathogens
Stomach acid and digestive enzymes destroy pathogens.

10. Second line of Defense: Specific Defenses
If a pathogen gets past the non-specific defenses, the immune system reacts with a series of specific defenses.
When activated by a pathogen it’s called an immune response.
Any substance, such as a virus or bacterium, that triggers this response is known as an antigen.

11. If a pathogen enters the body it makes an inflammatory response.
-is a non-specific defense reaction to tissue damage caused by injury or infection.

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Histamines Released-increase blood flow to injured area
Phagocytes- ingest and destroy pathogens and foreign matter
Neutrophine
Macrophage
Natural Killer cells
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Other Defenses
Temperature- Fever
Proteins- interferon- released by cells infected with viruses.
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14. 3rd Line of defense
The cells of the immune system that recognize specific antigens are: The body has been came in to contact with previous encountered pathogen.
Antibodies which are proteins that recognize and bind to an antigen marking it for destruction.
Memory cells- remember pathogens
B lymphocytes (B cells)-defend the body against antigens and pathogens in body fluids.
T lymphocytes (T cells)-defend the body against abnormal cells and pathogens inside living cells.
Antibody
Antigen

15. Second Line of Defense - Nonspecific
Inflammatory Response
Damaged tissues release histamines, increasing blood flow to the area.
Histamines cause capillaries to leak, releasing phagocytes to the wound.
Phagocytes engulf bacteria and destroy it
Platelets move out of the capillary to seal the wounded area.
infected tissue may become swollen and painful.
the core body temperature is raised causing a fever.
slows or stops the growth of pathogens and increases heart rate so white blood cells get to the site of infection faster.

16. Bacteria enter the wound
Skin
Wound
Phagocytes move into the area and engulf the bacteria and cell debris
Bacteria enter the wound
Capillary

17. There are three different types of immune system disorders:
allergies
autoimmune diseases
immunodeficiency diseases

18. Allergies An overreaction to a common antigen.
Common allergies include pollen, dust, mold, and bee stings.

19. What is an autoimmune disease?
When the immune system attacks the body's own cells.

20. Some examples of autoimmune diseases include:
Type I diabetes attacks insulin-producing cells.
Rheumatoid arthritis attacks connective tissues around joints.
Multiple sclerosis (MS) destroys functions of brain and spinal cord neurons.

21. Immunodeficiency Diseases
An immunodeficiency disease is one in which a person has a weakened immune response.
In one type of immunodeficiency disease, the immune system fails to develop normally.
A second type of immunodeficiency disease is AIDS.

22. Immunodeficiency Diseases
An immunodeficiency disease can be caused by the HIV virus. This can lead to the immunodeficiency disease called AIDS.

23. AIDS HIV attacks and destroys “helper” T-cells.
As the number of helper T cells decreases, the body becomes more susceptible to other diseases.

24. AIDS Preventing HIV Infection
HIV is NOT transmitted through casual contact.
The only no-risk behavior with respect to HIV and AIDS is abstinence.

25. AIDS Can AIDS Be Cured? At present, there is no cure for AIDS.
The virus can be controlled by expensive multidrug and multivitamin “cocktails” that fight the virus.