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 YouTube clip: Bacteria growth

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 protista (eukaryotes) YouTube clip: Monster’s Inside Me (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 protista (eukaryotes) – Parasites: grow and feed on a host tapeworms

Transmission Some carried by wind, water, direct contact, indirect contact… Some carried by vectors – Vector: object that carries a pathogen Examples: 1)Malaria – mosquitos carry the protozoan 2)Black Death – carried by flea’s of mice 3)West Nile Virus – carried by birds, but spread by mosquitoes

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

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 – T cells: destroy infected body cells – B cells: create antibodies YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC

Blood stream phagocyte bacteria phagocyte

Defense Proteins Antibodies – Created & released by B cells – Attach to antigens found on surface of invaders B cell antibody Y Y Y Y Y Y Y Y

Defense Proteins Antibodies – Created & released by B cells – Attach to antigens found on surface of invaders – How they help: 1) Bind to antigens of pathogen (like handcuffs) – Causes pathogens to clump – Easy targets for phagocytes 2) Weakens the cell membrane of pathogen – Causes them to burst

Y Y Y Y Y Y B CELLS MAKE ANTIBODIES ANTIBODIES ATTACH TO ANTIGENS OF THE PATHOGEN PHAGOCYTE DESTROYS PATHOGENS YY Y Y Y ANTIBODIES CAUSE THE PATHOGENS TO CLUMP TOGETHER Blood Stream Y Y Y Y Y YY Y Y Y Y Y phagocyte

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

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

Kobe Kuiz 1)Which part of our immune system coats the openings of the body? 2)Name and describe the two types of lymphocytes. 3)What are antibodies and how do they help keep us from harm? 4)Summarize how vaccines are created. 5)Which pathogen… absorbs nutrients from living tissue? are prokaryotic? 6)Which illness is spread by mice? 7)What is the vector of malaria?