Transcript The Immune System

1857
1883
Germ Theory
Louis Pasteur
hypothesizes that
disease is caused by
small organisms.
1928
1955
Today
Koch’s Postulates
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
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
Bacteria don’t grow around mold!!!
Koch’s Postulates
Robert Koch finds 4
conditions that prove a
pathogen causes a disease.
1857
1883
Polio Vaccine
Jonas Salk’s vaccine against polio becomes
available. Discontinued in the U.S. in 1994.
1928
1955
Today
Polio Comeback!
Germ Theory
Antibiotics
Louis Pasteur
hypothesizes that
disease is caused by
small organisms.
Sir Alexander Fleming
discovers penicillin.
Worldwide efforts
increase to vaccinate
people against polio.
 1st
line of defense: physical barrier
 Oils & sweat destroy some pathogens
• Some cells burst
• Some cells shrivel
 Coat
the openings of the body
 Nose, mouth, ears, eyes, genitals, anus
 Lined
with cilia & sticky fluids to trap
pathogens
Job: Search & destroy
 Phagocytes: surround & engulf invaders

• Phagocytosis (see animation)

Lymphocytes:
• T cells: destroy infected body cells
• B cells: Inactivate invaders
bacteria
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
• Infected cell
(left)
produces and
releases
interferon
• Uninfected
cell (right)
absorbs the
interferon and
creates
enzymes to
fight the
pathogen
virus
Virus
RNA
New virus
New virus
New virus
New virus
Interferon
proteins
New virus


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

Defined: microorganisms
that cause disease
• Viruses: turn cells into
virus making factories

Defined: microorganisms
that cause disease
• Viruses: turn cells into
virus making factories
• Bacteria: prokaryotes
that can release toxic
chemicals

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

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)

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


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 mosquitos
1)
2)
3)
4)
5)
6)
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…
1)
2)
7)
8)
absorbs nutrients from living tissue?
is prokaryotic?
Which illness is spread by mice?
What is the vector of malaria?