The Immune System

Pathogens Defined: microorganisms that cause disease – Viruses: turn cells into virus making factories

Pathogens Defined: microorganisms that cause disease – Viruses: turn cells into virus making factories – Bacteria: prokaryotes can release toxic chemicals

Pathogens Defined: microorganisms that cause disease – Viruses: turn cells into virus making factories – Bacteria: prokaryotes can release toxic chemicals – Fungi: pierce cells and absorb the nutrients

Pathogens Defined: microorganisms that cause disease – Viruses: turn cells into virus making factories – Bacteria: prokaryotes can release toxic chemicals – Fungi: pierce cells and absorb the nutrients – Protozoans: single celled protista (eukaryotes) Plasmodium causes malaria

Pathogens Defined: microorganisms that cause disease – Viruses: turn cells into virus making factories – Bacteria: prokaryotes can release toxic chemicals – Fungi: pierce cells and absorb the nutrients – Protozoans: single celled protista (eukaryotes) – Parasites: grow and feed on a host tapeworms

Transmission Some carried by wind, water, direct contact, indirect contact… Two of the dirtiest things you touch on a daily basis are…

Transmission Some carried by wind, water, direct contact, indirect contact… Vectors: organism that carries a pathogen Examples: 1)Malaria disease Cause: Plasmodium protozoa Vector: Mosquitos

Transmission Some carried by wind, water, direct contact, indirect contact… Vectors: organism that carries a pathogen Examples: 1)Malaria disease Cause: Plasmodium protozoa Vector: Mosquitos 2)Bubonic Plague Cause: Bacterium Yersinia pestis Vector: Fleas

Transmission Some carried by wind, water, direct contact, indirect contact… Vectors: organism that carries a pathogen Examples: 1)Malaria disease Cause: Plasmodium protozoa Vector: Mosquitos 2)Bubonic Plague Cause: Bacterium Yersinia pestis Vector: Fleas 3)Rocky Mtn. Spotted Fever Cause: Bacteria Rickettsia Vector: Ticks

The Skin 1 st line of defense: physical barrier Oils & sweat destroy some pathogens – Some pathogens burst…some shrivel Skin bacteria bacteria

Mucus Membranes Coat the openings of the body – Nose, mouth, ears, eyes, genitals, anus Lined with cilia & sticky fluids to trap pathogens Commonly inhaled: Viruses Bacteria Pollen Dirt Dust Fungal spores... virus bacterium fungus

Defense Proteins Antibodies – Created & released by lymphocytes – Attach (like handcuffs) to antigens of invader antigen Lymphocyte Y Y Y Y Y Y Y Y

Defense Proteins Antibodies – Created & released by lymphocytes – Attach (like handcuffs) to antigens of invaders – How do they kill? 1)Causes pathogens to clump Phagocyte (white blood cell)

Defense Proteins Antibodies – Created & released by lymphocytes – Attach (like handcuffs) to antigens of invaders – How do they kill? 1)Causes pathogens to clump 2)Weakens the cell membrane of the pathogen Bacterium YYY YYY Y Y antibody

Interferon 1)Cell becomes infected by virus 2)Infected cell sends interferon to healthy neighbors 3)Interferon causes healthy cell to create defense enzymes 4)Healthy cell able to fight virus Defense Proteins Virus RNA New virus Interferon virus Infected! Interferon New virus Not Infected!

White Blood Cells Job: Search & destroy

White Blood Cells Job: Search & destroy Type 1: Phagocytes – surround & engulf invaders by phagocytosis The bacterium is placed inside a lysosome… and digested into harmless fragments.

Blood stream phagocyte bacteria phagocyte

Cool Phagocyte Video Clip YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC

Blood Stream White Blood Cells Job: Search & destroy Type 1: Phagocytes – surround & engulf invaders by phagocytosis Type 2: Lymphocytes – create antibodies & destroy infected body cells B cell Lympho- cyte Y Y Y Y Y Y Y Y phagocyte

Cool Lymphocyte video clip YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC

Vaccination Prevents infections (not a cure) Vaccination process 1) Weakened pathogen is injected 2) Immune system produces… 1955: Jonas Salk created a vaccine for Polio

Dead virus Vaccination Prevents infections (not a cure) Vaccination process 1) Weakened pathogen is injected 2) Immune system produces… a) Antibodies to fight the weakened pathogen b) Memory cells for future infections Goal: Memory cells and antibodies kept for life 30 years later: What happens if you re-catch the living virus? B cell Lympho- cyte Y Y Y Y Y Y Y Y Y Y Y Memory B cell

The Celebrity Effect: Jenny McCarthy claims vaccines cause autism.

Vaccines Don't Cause Autism: Healthcare Triage

60 Minutes Australia - Vaccine Debate Story

Anti-Vaccination Church Has Measles Outbreak

Review 1)Which part of our immune system coats the openings of the body? 2)How do lymphocytes differ from phagocytes? 3)What are antibodies and how do they help keep us from harm? 4)Which pathogen… absorbs nutrients from living tissue? are prokaryotic? 5)Which illness is spread by mice? 6)What is the vector of malaria? 7)Why are people given dead/weakened pathogens?