the immune system history of medicine 1857 1883 1928 1955 today germ theory louis pasteur...
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The Immune System
History of Medicine
1857 1883 1928 1955 Today
Germ Theory
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.
Koch’s Postulates
Robert Koch finds 4 conditions that prove a
pathogen causes a disease.
History of Medicine
1857 1883 1928 1955 Today
Germ Theory
Louis Pasteur hypothesizes that
disease is caused by small organisms.
Koch’s Postulates
Robert Koch finds 4 conditions that prove a
pathogen causes a disease.
Antibiotics
Sir Alexander Fleming discovers
penicillin.
History of Medicine
1857 1883 1928 1955 Today
Germ Theory
Louis Pasteur hypothesizes that
disease is caused by small organisms.
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.
Antibiotics
Sir Alexander Fleming discovers
penicillin.
Polio Comeback!
Worldwide efforts increase to vaccinate people against polio.
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• How can pathogens be transferred?
• Indirect contact does NOT REQUIRE touching an infected individual.• Touching an infected surface• Breathing in infected air• Drinking contaminated water
• Direct contact REQUIRES touching an infected individual. • Kissing• Hand shaking • Sexual intercourse
Transmission Through Vectors• Defined: organism that
carries a pathogen
Examples:1) Malaria – mosquitos
carry the protozoan2) Black Death – carried by
fleas of mice3) 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
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 cells– B cells produce antibodies, which deactivate the pathogen.
YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC
YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC
Blood stream
Defense Proteins• Antibodies
– Created & released by lymphocytes
– Attach to antigens (like handcuffs)
lymphocyte
antibody
YYY
YYY
Y
Y
Defense Proteins• Antibodies
– Created & released by lymphocytes
– Attach to antigens (like handcuffs)
• How do they kill?1) Causes pathogens to
clump2) Weakens the cell
membrane of the pathogen
B
B
BYY Y
Y
Y
Y
B CELLS MAKE ANTIBODIES
ANTIBODIES ATTACH TO ANTIGENS OF THE PATHOGEN
PHAGOCYTE DESTROYS PATHOGENS
YY
Y
YY
ANTIBODIES CAUSE THE PATHOGENS TO CLUMP TOGETHER
B
B
BBlood Stream
Y
Y
Y
Y
Y
Y YY
YY
YY
phagocyte
• Interferon1) Cell becomes
infected by virus2) Infected cell
sends interferon to healthy neighbors
3) Interferon causes healthy cell to create defense enzymes
4) Healthy cell able to fight virus
Defense ProteinsVirus RNA
New virus
New virus
New virusInterferon
virus
Infected!
InterferonInterferon
New virus
New virus
Not Infected!
Immunity • In all types of immunity, pathogens are
destroyed before you get sick.– Passive immunity occurs without
an immune response.• Mother’s milk• Genetics
– Active immunity occurs after aspecific immune response.• Having chicken pox
– Acquired Immunity occurs after given a vaccine.• Flu shot
Vaccination• Prevents infections (not a
cure)• Vaccination process
– Weakened/dead pathogen or antibodies are 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
ReView1) 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) What is the skin’s role in immunity?5) How can pathogens be transferred?6) Who hypothesized that disease is caused by small organisms?7) Which pathogen…
a. Absorbs nutrients from living tissue?b. Are prokaryotic?
8) What is the vector of malaria?9) What are the differences between passive, active, and acquired
immunity? 10) How do vaccines work?