Transcript Chapter 31 Pathogens and Illness

Chapter 31
Immune System & Disease
In the 1850’s Pasteur proposed the
Germ Theory
Specific microorganisms cause disease
Types of pathogens that cause disease.
Bacteria
Viruses
Fungi- occur in warm damp areas
Protozoa
Parasites
How are Bacteria
and Viruses
Different?
Bacteria
The Prokaryotes
•Reproduce by Binary Fission
•Autotrophic and Heterotrophic
Helpful
Bacteria in Nature
Decomposers
Nitrogen cycle
Industry
Food- yogurt!
Harmful Bacteria
Cause disease by
 Releasing toxins into the body
 Directly break down tissue of
organism for food
Viruses
Latin for Poison
• Not living
•Require a host cell to
reproduce!!
•Consist of DNA or
RNA surrounded by a
protein coat
Viral Infection
Virus enters host cell
Host cell produce viral DNA
Host cell bursts
Retroviruses
Viruses that have RNA as their genetic material
HIV leads to AID’s
HIV kills our
Helper T cells
Common Viruses
Flu
Chicken Pox
Warts
Mono
Rabies
Treatment
Bacteria
Antibiotics
Viruse
s
Vaccination
Vaccination
Immunity from
vaccination can be
temporary or
permanent
How our Bodies
defend against
pathogenic
organisms
Nonspecific
vs.
specific defenses
Nonspecific Defense
Skin- the most important!
Oil and sweat create an
acidic environment
Mucus, saliva, sweat, tears,
contain lysosomes that break
down bacterial cell walls
Inflammatory responsefever and swelling
Types of Immunity
Active
 Body mounts an
active response to the
pathogen
 The development of
antibodies in
response to
stimulation by an
antigen
 Produced by
vaccination or
getting the disease
Passive
 Temporary immunity
 A mother provides
passive immunity to
her baby in her uterus
and after birth by
breastfeeding
Specific Defense
The Antibody Antigen Reaction
An antigen triggers an immune system response
Antigens are specific for each pathogen
Lymphocytes produce antibodies.
Once formed the antibodies are held in memory B
cells (lymphocytes) so that the body has
permanent immunity to that disease
• Antibodies help kill the
intruder by:
1. Binding to antigens
on surface of
microbes
2. Clustering antigens
together