The Immune SystemSneeze

History of Identifying Pathogens

Robert Koch (1843-1910): “father of disease”-research focused on anthrax (bacteria).

Koch’s Postulates:-rules for determining the cause of a disease or illness.

Infectious Diseases

Pathogens: anything foreign that enters your body and can make you sick.Examples- bacteria, viruses, protists, fungi & non-harmful substances.

Modes of Transmission:AirFoodWaterPerson-to-person contactAnimal bites (vector)

Human Diseases & Conditions

Disease/Condition Pathogen Mode of Transmission

AIDS Virus (HIV) bodily fluids

Common Cold Coronavirus air, physical contact

Malaria Plasmodium falciparum mosquitoes

Measles Paramyxovirus air, physical contact

Botulism Clostridium botulinum contaminated food

Tetanus Clostridium tetani physical contact

Athlete’s Foot Trichophyton rubrum physical contact

First Line of Defense: Barriers

Structures:Skin Oil (sebum)Mucous MembranesTearsSalivaEar wax Hair/Cilia

Second line of Defense:NonSpecific Immunity

NonSpecific Immunity includes:1. Inflammatory Response2. Temperature Response3. Proteins

1. Inflammatory Response: series of reactions that suppress infection and speed recovery.

a. Histamine released (Increases blood flow to site of injury/infection; can cause redness, swelling, warmth, and pain)

b. Phagocytes- white blood cell that ingest and destroy pathogens.Examples: Neutrophils, Macrophages &

Natural Killer Cells – attack pathogen infected cells.

2. Temperature Response-Fever: sign body is responding to infection; suppresses growth and reproduction; promotes action of white blood cells.

3. Complement System- Proteins:20 different proteins used to fight off pathogens,

Exp.: Interferon- protein that inhibits reproduction of

viruses.

Third Line of Defense: The Immune System & Response

Immune System Structures

1. Bone Marrow-Produces white blood cells lymphocytes-Two types: B cells & T cells

2. Thymus – gland in the chest

-Place of maturation of T-cells

3. Lymph & Lymph Nodes-Filter pathogens, lymphocytes

4. Spleen-Filters pathogens from blood

5. Tonsils & Adenoids

-Contain lymphocytes which are important for antibody production.

The Immune Response:Let the Battle Begin!1. Macrophage engulfs a pathogen.

2. Helper T-cells (lymphocyte) bind with macrophages to fight the pathogen and release specialized proteins (Interleukin).

3. Specialized proteins stimulate additional protein release that stimulate additional Helper T-cells and Cytotoxic T-cells.

A. Cell-Mediated Immune Response-Cytotoxic T-cells & Suppressor T-cells-destroy infected cells-shut down response after pathogens are cleared

B. Humoral Immune Response-B cells change into plasma cells and produce antibodies.

Antibodies – chemicals that binds to antigen to disable the pathogen (block reproduction).

-Antigen specific-Antibodies are stored for future use

-Memory Cells (lymphocytes) are produced and remain in the body long term for future pathogen attacks.

Immunity & Vaccination

1. Immunity-the ability to resist an infectious disease.

-Memory cells -Vaccinations

2. Vaccine-solution that contains a dead or weakened pathogen.

-Body initiates a primary immune response.Memory cells remain for future possible infections.

-Booster shots

Problems of the Immune System:

Allergies

Asthma

Autoimmune Diseases- immune system attacks your own body cells. (lupus, MS, type I diabetes, rheumatoid arthritis)

HIV and AIDS• AIDS- Acquired Immunodeficiency Syndrome

– The immune system loses its ability to fight off pathogens and cancers• AIDS results from infection by HIV

– HIV-Human Immunodeficiency Virus

Destroys Helper T cells cripples the immune system leads to AIDS

• Opportunistic Infections-illnesses caused by pathogens that produce disease in people with weakened immune systems– Usually these pathogens don’t create problems in healthy people

• HIV does NOT cause death, but AIDS is fatal– Death caused by weakened immune system’s inability to fight

opportunistic infections and cancers• HIV is transmitted by body fluids and contaminated needles

*PLAY DISCOVERYEDUCATION VIDEO*

Type of Cell Function

Phagocyte Ingest and destroy pathogens.

Neutrophil Type of phagocyte, most abundant, attacks and destroys pathogens.

Macrophage Type of phagocyte, attacks and destroys pathogens.

Natural Killer Cells Attack pathogen infected cells, cancerous cells, and virus infected cells.

B Cells Lymphocyte, made in bone marrow, changes in to Plasma cells.

T cells Lymphocyte, made in bone marrow, sent to thymus for maturation.

Helper T cells Lymphocyte, helps with the initial steps of the immune response by binding with a macrophage.

Cytotoxic T cells Lymphocyte, destroys infected cells, cancer cells, and parasites.

Suppressor T cells Lymphocyte, shuts down the immune response when all pathogens are gone.

Plasma cells Lymphocyte, type of B cell that makes antibodies.

Memory cells Lymphocyte, attacks pathogens later, not the first time.