The Immune System
Louis Pasteur hypothesizes that disease is caused by small organisms. History of Medicine 1857 1883 1928 1955 Today Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.
History of Medicine Koch’s Postulates Robert Koch finds 4 conditions that prove a pathogen causes a disease. 1857 1883 1928 1955 Today Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.
History of Medicine Koch’s Postulates Robert Koch finds 4 conditions that prove a pathogen causes a disease. History of Medicine 1857 1883 1928 1955 Today Antibiotics Sir Alexander Fleming discovers penicillin. Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.
Bacteria don’t grow around mold!!!
History of Medicine Koch’s Postulates Robert Koch finds 4 conditions that prove a pathogen causes a disease. Polio Vaccine Jonas Salk’s vaccine against polio becomes available. Discontinued in the U.S. in 1994. 1857 1883 1928 1955 Today Polio Comeback! Worldwide efforts increase to vaccinate people against polio. Antibiotics Sir Alexander Fleming discovers penicillin. Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.
The Skin 1st line of defense: physical barrier Oils & sweat destroy some pathogens Some cells burst Some cells shrivel
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 Phagocytes: surround & engulf invaders Phagocytosis (see animation) Lymphocytes: T cells: destroy infected body cells B cells: Inactivate invaders
phagocyte bacteria phagocyte
Defense Proteins Antibodies Proteins made by B cells How can they help: 1. Bind to antigens of pathogen (like handcuffs) Causes pathogens to clump Easy targets for phagocytes 2. Weakens the cell membrane Causes them to burst
Defense Proteins Interferon virus Interferon Infected cell (left) produces and releases interferon Uninfected cell (right) absorbs the interferon and creates enzymes to fight the pathogen Virus RNA New virus New virus New virus New virus Interferon proteins New virus
Vaccination Prevents infections (not a cure) Vaccination process Weakened pathogen is injected Antigens on pathogen Immune response: Production of memory cells (future infections) Antibodies bind to antigens (current infection) Goal: Speed up immune response if you encounter the unweakened virus
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)
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
Pathogens (contd) Some carried by wind, water, direct contact, indirect contact… Some carried by vectors Vector: object that carries a pathogen Examples: Malaria – mosquitos carry the protozoan Black Death – carried by flea’s of mice West Nile Virus – carried by birds, but spread by mosquitos
Kobe Kuiz What did Louis Pasteur contribute to our knowledge of medicine? Which part of our immune system coats the openings of the body? Name and describe the two types of lymphocytes. What are antibodies and how do they help keep us from harm? Summarize how vaccines are created. Which pathogen… absorbs nutrients from living tissue? is prokaryotic? Which illness is spread by mice? What is the vector of malaria?