Download The Immune System

The Immune System
History of Medicine
1857
1883
Germ Theory
Louis Pasteur
hypothesizes that
disease is caused by
small organisms.
1928
1955
Today
Koch’s Postulates
History of Medicine
Robert Koch finds 4
conditions that prove a
pathogen causes a
disease.
1857
1883
Germ Theory
Louis Pasteur
hypothesizes that
disease is caused by
small organisms.
1928
1955
Today
Koch’s Postulates
History
of
Medicine
Robert Koch finds 4
conditions that prove a
pathogen causes a
disease.
1857
1883
1928
1955
Germ Theory
Antibiotics
Louis Pasteur
hypothesizes that
disease is caused by
small organisms.
Sir Alexander
Fleming discovers
penicillin.
Today
Koch’s Postulates
History
of
Medicine
Robert Koch finds 4
Polio Vaccine
conditions that prove a
pathogen causes a
disease.
1857
1883
Jonas Salk’s vaccine against polio
becomes available. Discontinued in
the U.S. in 1994.
1928
1955
Germ Theory
Antibiotics
Louis Pasteur
hypothesizes that
disease is caused by
small organisms.
Sir Alexander
Fleming discovers
penicillin.
Today
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 – mosquitoes
carry the protozoan
2) Black Death – carried by
fleas of mice
3) 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
White Blood Cells
• Job: Search & destroy
YouTube Clip: Types of
White Blood Cells
(lymphocytes) from the BBC
YouTube Clip: Types of
White Blood Cells
(phagocytes) from the BBC
White Blood Cells
• Job: Search & destroy
• Type 1: Phagocytes
– Surround & engulf invaders by phagocytosis
YouTube Clip: Types of
White Blood Cells
(lymphocytes) from the BBC
YouTube Clip: Types of
White Blood Cells
(phagocytes) from the BBC
White Blood Cells
YouTube Clip: Types of
White Blood Cells
(lymphocytes) from the BBC
• 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.
Blood
stream
Defense Proteins
• Antibodies
– Created & released by
lymphocytes
– Attach to antigens (like
handcuffs)
antibody
Y
Y
lymphocyte
Y
Defense Proteins
• Antibodies
– Created & released by
lymphocytes
– Attach to antigens (like
handcuffs)
• How do they kill?
1) Causes pathogens to
clump
2) Weakens the cell
membrane of the
pathogen
B CELLS MAKE ANTIBODIES
ANTIBODIES ATTACH TO ANTIGENS OF THE PATHOGEN
Y
Y
Y
Y Y
Y
YY
YY
Y
Y
Blood
Stream
Y
Y
Y Y
Y
Y
Y
phagocyte
Y
Y
Y
ANTIBODIES CAUSE THE PATHOGENS TO CLUMP TOGETHER
PHAGOCYTE DESTROYS PATHOGENS
Y
Defense Proteins
• 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
virus
Virus
RNA
New virus
New virus
New virus
New virus
Interferon
New virus
Infected!
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 a
specific 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 antigens
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
ReView
1)
2)
3)
4)
5)
6)
7)
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?
What is the skin’s role in immunity?
How can pathogens be transferred?
Who hypothesized that disease is caused by small organisms?
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?