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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 that can release toxic chemicals.
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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 that can release toxic chemicals
Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories • Bacteria: prokaryotes that 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 that can release toxic chemicals • Fungi: pierce cells and absorb the nutrients • Protozoans: single cells protista (eukaryotes) Plasmodium causes malaria
Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories • Bacteria: prokaryotes that can release toxic chemicals • Fungi: pierce cells and absorb the nutrients • Protozoans: single cells. Protists (eukaryotes) • Parasites: grow and feed on a host tapeworms
Transmission • Some carried by wind, water, direct contact, indirect contact… • Vectors: organism that carries a pathogen Examples: • Malaria – mosquitos carry the protozoan • Black Death – carried by fleas of mice • West Nile Virus – carried by birds, but spread by mosquitoes
The Skin • 1st line of defense: physical barrier • Oils & sweat destroy some pathogens • Some pathogens burst…some shrivel bacteria bacteria Skin
Mucus Membranes • Coat the openings of the body • Nose, mouth, ears, eyes, genitals, anus • Lined with cilia & sticky fluids to trap pathogens
YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC White Blood Cells • Job: Search & destroy
YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC White Blood Cells • Job: Search & destroy • Type 1: Phagocytes • surround & engulf invaders by phagocytosis
YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC White Blood Cells • Job: Search & destroy • Type 1: Phagocytes • surround & engulf invaders by phagocytosis • Type 2: Lymphocytes • create antibodies & destroy infected body cells
phagocyte Blood stream bacteria phagocyte
Defense Proteins • Antibodies • Created & released by lymphocytes • Attach to antigens (like handcuffs) antibody Y Y Y Y Y lymphocyte Y Y Y
Defense Proteins • Antibodies • Created & released by lymphocytes • Attach to antigens (like handcuffs) • How do they kill? • Causes pathogens to clump • Weakens the cell membrane of the pathogen
B CELLS MAKE ANTIBODIES ANTIBODIES ATTACH TO ANTIGENS OF THE PATHOGEN Blood Stream B B B B Y Y Y Y Y Y Y Y Y Y Y Y phagocyte Y Y Y B B Y Y Y Y Y Y Y Y ANTIBODIES CAUSE THE PATHOGENS TO CLUMP TOGETHER PHAGOCYTE DESTROYS PATHOGENS
Defense Proteins virus Virus RNA New virus New virus New virus New virus Interferon Interferon Interferon New virus Infected! Not Infected! • Interferon • Cell becomes infected by virus • Infected cell sends interferon to healthy neighbors • Interferon causes healthy cell to create defense enzymes • Healthy cell able to fight virus
Vaccination • Prevents infections (not a cure) • Vaccination process • Weakened pathogen is injected • Immune system produces… • Antibodies to fight the weakened pathogen • Memory cells for future infections • Goal: Speed up immune response if you encounter the actual virus
Review • Which part of our immune system coats the openings of the body? • How do lymphocytes differ from phagocytes? • What are antibodies and how do they help keep us from harm? • Which pathogen… absorbs nutrients from living tissue? are prokaryotic? • Which illness is spread by mice? • What is the vector of malaria?