Did you know? We have 10 times more bacteria cells in our bodies than human cells.

Immune System Purpose: to protect our bodies from infection and pathogens Pathogens: Disease-causing agents

Immune System Our body has several types of defenses against pathogens

Types of Pathogens Travel with your table to 4 stations around the room Take notes in the provided graphic organizer Bacteria Viruses Parasites Fungi

Bacteria Single-celled organisms Release chemicals that are toxic to the host which destroys healthy body cells Examples: food poisoning, tuberculosis, syphilis

Viruses Strands of DNA or RNA surrounded by a protein coat Take over a healthy cell and cause it to produce more viruses Examples: HIV, flu, herpes

Fungi Multi-cellular organisms (except for yeast) Pierce healthy cells and take the cell’s nutrients Examples: Athlete’s foot, pneumonia

Parasites Organisms that grow and feed on their host Some kill while others drain the body’s resources Examples: Tapeworms, Malaria, Scabies

How Your Body Protects Itself Skin Protective layer for organs Secretes sweat, making it acidic and harmful for pathogens Mucous membranes Lines all openings in the body (eyes, nose, mouth, ears, etc.) Traps pathogens in cilia (tiny hair like structures) before they enter the body

How Your Body Fights Back White blood cells: Find and kill pathogens that have made it past the skin and mucous membranes Phagocytes: engulf pathogens to destroy them T cells: destroy body cells already infected with the pathogen B cells: produce proteins that inactivate pathogens that have yet to infect other cells

How Your Body Fights Back Proteins Antibody: Proteins made by B cells that attack pathogens in action Immunity: Failure to get sick in the presence of a pathogen Passive: occurs by immunity being passed down from mother to child Active: happens after body has successfully responded to a pathogen before

How Your Body Responds Occurs when pathogen enters the body or tissue gets damaged Inflammation Body rushes blood to the site to provide WBC’s Results in swelling, redness, pain, itching and increased warmth at the site

Overreactions of the Immune System Allergy: An oversensitivity to a harmless antigen Autoimmune disease: Immune system cannot tell the difference between healthy and unhealthy body cells Examples: Type 1 Diabetes, Multiple Sclerosis

How Your Body Responds Fever Chemicals are released to increase body temperature, which helps WBC’s mature faster High fevers are dangerous because they denature enzymes that are vital to the body

Medication Antibiotics Target bacteria or fungi and keep them from growing or reproducing Antibiotic resistance occurs when bacteria mutate so that they are no longer affected by antibiotics

Medication Vaccines Substance that contains the antigen (antibody producer) of a pathogen Body produces necessary defenses without getting sick

HIV/AIDS

HIV Read the back of your graphic organizer

AIDS Acquired Immunodeficiency Syndrome

The Difference HIV is a virus AIDS is the final result of HIV